protect home from high winds

8/11/2019 Protect Home From High Winds

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Stronger Homes

Stronger

Communities

ConstructionTechniquesto Protect Homes fromHigh Wind Damage

CLEMSONU N I V E R S I T Y



Construction

Techniquesto Protect Homes from

High Wind Damage



Disclaimer

The material contained in this publication was prepared by Clemson

University, Department of Civil Engineering , the S.C. Sea Grant Exten-

sion Program and the Blue Sky Foundation of North Carolina, Inc., a

nonprofit corporation. This work was completed and funded by The

State of North Carolina Department of Crime Control and Public Safety

Division of Emergency Management and FEMA through several HMGP

Grants. Neither Clemson University, the Blue Sky Foundation of North

Carolina Inc., the State of North Carolina, the North Carolina Depart-

ment of Crime Control and Public Safety Division of Emergency Manage-

ment or FEMA, the acknowledged individuals, nor any person acting on

behalf of them: (a) makes any warranty, expressed or implied, with re-

spect to the use of any information, apparatus, method, or process dis-

closed in this publication that such use may not infringe privately owned

rights; or (b) assumes any liability with respect to the use of, or for direct

or consequential damages resulting from the use of, any information,apparatus, method or process disclosed in this publication; or (c) has any

liability for damages that result from any negligent act or omission in-

volved in the preparation of this material. Any implied warranty of

merchantability of fitness for a particular use is specifically excluded. Any

person, organization, or entity public or private agrees to hold Clemson

University, the Blue Sky Foundation Inc., the State of North Carolina,

the North Carolina Department of Crime Control and Public Safety

Division of Emergency Management, and FEMA harmless from any harm,

damage or injury resulting from the use of these materials or any process

described therein.



Table of Contents

Chapter 1: Roof Systems .................................................................. 1

1.1 Sheathing .................................................................... 2

1.2 Underlayment .............................................................. 8

1.3 Flashing........................................................................ 91.4 Asphalt Shingles ......................................................... 10

Chapter 2: Wall Systems .................................................................. 15

2.1 Windows ...................................................................... 16

2.2 Exterior Doors.............................................................. 22

2.3 Garage Doors ............................................................... 24

Chapter 3: Light Framing ................................................................. 31

3.1 Roof Framing ............................................................... 32

3.2 Wall Framing ............................................................... 44

3.3 Foundations ................................................................. 49

Chapter 4: Concrete and Masonry ................................................... 53

4.1 Roof Framing ............................................................... 54

4.2 Masonry Wall Connection .......................................... 56

4.3 Foundations ................................................................. 56

Appendix ..................................................................................... 59

Table A. Minimum Roof Sheathing Panel Thickness ......... 59

Table B.1. Roof Sheathing Nailing Schedule:

Southern Yellow Pine .................................................. 59

Table B.2. Roof Sheathing Nailing Schedule:

Spruce Pine Fir ............................................................ 60

Table C. Corrosion ............................................................... 61

Table D. Window Selection Guide ...................................... 62

Table E. Required Uplift Loads ............................................ 63

Table F. Stud Selection ......................................................... 64

Reference Materials for High Wind Construction .............. 65

Acknowledgements .............................................................. 68


http://slidepdf.com/reader/full/protect-home-from-high-winds 6/732002 Construction Techniques 1

Chapter 1

Roof Systems


http://slidepdf.com/reader/full/protect-home-from-high-winds 7/732 2002 Construction Technique

Roof Systems

In typical residential construction, roof systems are comprised of three

major elements: (1) roof covering, (2) roof underlayment, and (3) roof

sheathing. Each of these elements plays a critical role in maintaining a

house’s integrity during a high wind event.

1.1 SheathingRoof sheathing can become detached by high winds. Negative pressure

from above, with positive pressure from below, can cause inadequately

nailed sheathing to tear from the roof framing. The positive pressure from

below is increased at eave and gable overhangs. The negative pressure

from above is higher at the edges of the roof. The roof perimeter has

higher pressure due to higher turbulence at the edges of the roof. The

thickness and nailing of the roof sheathing must be adequate to resist

these combined forces so that the sheathing preserves the diaphragm and

maintains the skin of the building.

When retrofitting a roof the

first step should be to strip

away all the existing roof

materials, shingles and

underlayment, leaving only

the sheathing. Past

performance shows that a

second layer of roof

coverings does not perform

as well as a layer attached

directly to the sheathing.

Once all roofing materials

have been removed, each

structural sheathing panel orlumber sheathing board

should be inspected. If any

panels or boards show signs

of deterioration, these panels

or boards should be

replaced.

Boarded roofs are no longer

common in new

construction, but may be

encountered when re-

roofing. If any boards need

replacing, use structural

panel sheathing of same

thickness as replacement.

Once any sheathing panels are lifted by a hurricane’s winds, the entire

structure is more vulnerable to damage; the wind can pressurize the attic

space and force off more sheathing panels. Roof sheathing is most

vulnerable at the eaves, corners and ridges where the wind pressure is the

highest. When sheathing panels are removed, trusses or rafters become

exposed and unstable and the entire roof may collapse. This loss of all or a

portion of the roof system allows rain to enter the building. Water damage

has caused a significant percentage of interior damage in recent storms. To

Figure 1.1: Wind pressures on enclosed and partially enclosed buildingsSource: FEMA-55 Coastal Construction Manual



maintain the integrity of the house envelope, it is important that the

connections at roof corners and at eaves and ridges be as strong as possible.

Materials

The minimum panel thickness for a rafter/truss spacing of 24” is 5/8”. The

maximum span for all rafter/truss spacing is 24”. These values are based

on 3-second gust speeds of 140 mph for the North Carolina coastline. If the area of interest is different, see Table A in the Appendix for appropri-

ate values.

Layout

Apply structural sheathing panels with the long dimension perpendicular

to the roof framing. Start sheathing with the full 4’ width at the eaves

and ridges, so that no sheet is less than 4’ wide at the roof edge(s). All

sheathing must be attached to at least three rafters/trusses with staggered

end joints. If a row of panels must be installed that is less than four feet in

width, this make-up row should be at least 2’ wide and placed in the

middle of the roof slope. It may be necessary to have two rows of make-up

panels to accomplish this. If a make-up panel less than eight feet in

length is required within a given row, it should be placed in the middle of

a row, not at either end, but span at least three rafters. To accomplish

this, it may be necessary to use two panels, each one less than 8 feet in

length.

F u l l w

i d t h

a t h i p

M a k e u p s h e e t s

a t t a c h e d t o a t l e a s t

t h r e e r a f t e r s / t r u s s e s

T w o b a y m i n i m u m F u l l l e n g t h a t r i d g e

F u l l l e n g t h a t r i d g e

F u l l l e n g t h a t e a v e

F u l l l e n g t h a t e a v e

T w o b a y m i n i m u m

F u l l w

i d t h

a t h i p

M a k e

u p

s h e e t s

2 4 ”

2 4 ” m

i n

m i n

Figure 1.2a: Hip Roof Sheathing Layout



Panels or boards in good

condition should still be in-

spected from the attic space

to determine if connection to

rafters and trusses is ad-

equate. The attachment of

the roof sheathing to the framing members is consid-

ered the most important con-

nection to maintain during a

high wind event. This con-

nection should be strength-

ened if more than 5 percent

of the sheathing fasteners,

staples or nails, miss the

framing members. Both legs

of a staple must be driven

into the framing member for

it to be effective. The con-

nection should also be

strengthened if the nailing

pattern is less than the roof

sheathing nailing schedule

shown in Table 1.1. Nails

that missed the roof framing

members present the oppor-

tunity to estimate nail size as

well. The size of the fasten-

ers is an important consider-

ation in determining if addi-

tional fasteners are required.

Figure 1.2d: Example 2

6’

8’ 4’

6’ 6’8’ 8’

6’ 8’ 8’

Ridge

Eave

Make-up sheets

Figure 1.2c: Example 1

Fullwidth

sheetatridge

Ridge

Eave

2.5’

2.5’

4’

Fullwidth

sheetateave

Make-up strips

Figure 1.2b: Gable Roof Sheathing Layout

Note: Framing members or blockingrequired at all sheet edges withtwo bays of gable end wall




N e a r f u l l l e n g t h s h e e t a t r a k e r i d g e

Overhang depthplus two bayminimum

M a k e - u p s h e e t s


N e a r f u l l l e n g t h s h e e t a t r a k e r i d g e

Overhang depthplus two bay

minimum





F u l l w

i d t h

s h e e t a

t r i d g

e

N e a r f u l l l e n g t h s h e e t a t r a k e / e a v e

N e a r f u l

l w i d t

h

s h e e t a

t e a v

e

N e a r f u l l l e n g t h s h e e t a t r a k e / e a v e

2 4 ”

2 4 ”

M i n .

M i n .

M a k e

- u p s

h e e t s



For example, a roof with a 17’ length along the slope has a make-up span

of one foot. Since the minimum allowable width for make-up sheets is 2’,

a one-foot make-up sheet cannot be used. To meet the minimum require-

ment two 2.5’ make-up rows must be used. Therefore, instead of four full

4’ wide strips and a 1’ wide make-up sheet, the roof will have 3 full 4’ wide

sheets and two 2.5’ wide make-up sheets located in the middle of the roof

See Example 1 (Figure 1.2c).

A roof with a 34’ length along the eave and 24” rafter/truss spacing has a

make-up span of two feet. Since the minimum allowable length is two

bays, a 2’ make-up sheet cannot be used. To meet the minimum require-

ment two make-up sheets must be used to span 10’. See Example 2

(Figure 1.2d).

Topside Attachment of Sheathing

The roof sheathing should be fastened with corrosion-resistant 8d

deformed (ring) shank nails. For other fastener recommendations, see the

2001 Wood Frame Construction Manual. See Appendix Table C for

corrosion resistance recommendations. The minimum nail spacing can be

found in Table 1.1 below. Nails must be properly driven with heads flush

to the surface of the sheathing.

To strengthen the attachment

of the sheathing, add #8

screws or 8d deformed (ring)

shank nails to the existing nail

pattern. In general, improv-

ing this connection is fairly

easy and inexpensive. Be-cause of its importance,

strengthening should be con-

sidered if there is any doubt

about the condition of the

current roof sheathing con-

nection.

Source: 2001 Wood Frame Construction ManualThis table is based on 140 mph 3-second gust speed. For other wind speeds, see

Appendix B.G = specific gravity

Table 1.1 Roof Sheathing Nailing Schedule

Southern Yellow Pine (SP) G≥0.49 Spruce Pine Fir (SPF) G<0.49

Rafter/Truss Nail Spacing at Nail Spacing at Nail Spacing Nail Spacing atSheathing Spacing Panel Edge Interior Supports at Panel Edge Interior Supports

Location (inches o.c.) (inches o.c.) (inches o.c.) (inches o.c.) (inches o.c.)

12 6 6 6 64’ Perimeter 16 6 6 4 4Edge Zone 19.2 6 6 4 4

24 4 4 3 312 6 12 6 12

Interior Zone 16 6 12 6 1219.2 6 12 6 1224 6 12 6 6



In situations where nailing is not possible, such as retrofit or sheathing

attachment without removing roof coverings, construction adhesives or

structural foams can be used. The construction adhesives are used to attach

additional lengths of wood trim to the existing roof structural members and roof

sheathing. One option is to add wood trim and then secure each new piece into

place while the adhesive cures to achieve maximum strength. This techniquerequires cutting 1"x 2" blocks of wood each 6" in length. The blocks are

installed with a 1 / 4" bead of construction adhesive applied evenly along the entire

6" length of the blocks' corner." The blocks are placed on 15" o.c. on both

sides of the framing member’s length. If there is only access to one side of a gable

end rafter, the glued block spacing should be decreased or made continuous.

See Figure 1.3. Another option is to attach a strip of 3 / 4” wide quarter round

trim piece along the length of the member on both sides using a 1 / 4” bead of

construction adhesive applied evenly along the length. Press the trim piece into

the uncured adhesive and secure in place with finish nails. See Figure 1.4.

Adhesives should be AFG-01 approved.

Figure 1.3: Wood Trim and Construction Adhesive Installation Illustration

Figure 1.4: Quarter Round Trim Adhesive Application Illustration

Sheathing

Glued Surface

Rafter/Truss

Finish NailsFinish Nails



Figure 1.5: Structural Foam Application Illustration

Sheathing

Structural FoamRafter/Truss

Underside Attachment of Sheathing

Structural foam can also be used to strengthen the sheathing-framing member

connection. The foam should be designed for structural applications. This

foam starts as a two-part solution that is sprayed from a specially designed

application machine. This allows the product to be applied in areas where it

may be difficult to reach the members. Figure 1.5 shows how the foam is

sprayed along the length of the framing member at the joint between the member

and the sheathing. The foam undergoes a catalytic reaction and begins curing

immediately. Once it has cured, it created a bond between the framing member

and the sheathing that has been tested as 2 to 4 times stronger than a

mechanically fastened connections.

Structural foam may be difficult to apply to an existing roof. Access to some

joints may be obscured.



Sealing of Sheathing Joints

Self-adhering polymer modified bitumen sheet or rubberized asphalt

underlayment should be applied to all joints of sheathing from the

topside. Each strip should be a minimum of 6” wide.

An alternative to the tape is to apply a quarter inch bead of caulk or

construction adhesive to both sides of the rafter or truss where it meets

the roof sheathing as well as the butt of all joints in sheathing panels. For

step-by-step instructions go to page four of Holding on to Your Roof

located at www.bluesky-foundation.com/details/hotyr.pdf/.

1.2 Underlayment

Materials

The underlayment should be two layers of 15-pound or greater roofing

felt.

Layout

Start with a metal drip edge along the eave. Next, place a 19” strip of

underlayment felt parallel with and starting at the eaves. Starting at the

eave apply 36” wide sheets of underlayment, overlapping successive sheet

19”. Attach a metal drip edge over the underlayment at each rake and

under the underlayment at the eave.

Figure 1.6: Sheathing Seams Sealed Using Bituminous Tape

There is no method to

provide a secondary

moisture barrier to planked

roof decks, given the

number of joints in the

system.



Attachment

All underlayment should be fastened with nails and 1” diameter tags,

metal or plastic. If metal tags are used, they must be of same or similar

metal as the nails used to prevent a chemical reaction between the two

metals. These tags help to spread the fastener load to prevent the nail

heads from being ripped through the underlayment. Nails and tags should

be corrosion resistant. See Appendix Table C for corrosion resistance

recommendations. Along the overlapping rows and at the end laps, nails

should be spaced at 6” o.c. The nail spacing in the field of the

underlayment should be 12” o.c. All nail spacing is minimum spacing.

This overlap and nail pattern helps prevent the loss of the underlayment

layer in the event of the loss of the roof covering.

For added protection the first strip of underlayment can be replaced with

self-adhering polymer modified bitumen sheet no less than 3’ wide.

To improve its waterproofing capability and its adhesion to the roof deck,

hot asphalt can be mopped on the deck before the underlayment is laid in

place.

Figure 1.7: Underlayment Layout and Attachment

Metal drip edge recover underlayment

19” wide #15 asphaltfelt underlayment

#15 asphalt feltunderlayment. (typ.)

Metal drip edgerecommended under

underlayment.(typ. at eave)

Nail 12” o.c. centeredbetween side laps.

Attach underlayment atlocations with low-prohcapped-head nails or thdisks attached with rooAll nails and disks shalcorrosion resistant.

Nails 6” o.c. a2”side laps

Lap ends 4”. Offsetlaps 3” min. (typ.)

Provide 7 nails atend laps. (typ.)

Provide 4 nails atend of first course.



1.3 FlashingTo exclude water from entry in all cases where openings through roofs

have borders that are flush with or protrude beyond roof coverings, the

opening should be carefully flashed. Well-installed flashings protect the

structure from water damage. Flashing should be applied at all roof slope

changes, such as valleys and ridges. Flashing should also be applied to all

roof penetrations, such as chimneys, vents, skylights, etc., and anytime

two unlike materials come together. Flashing should be installed above

the underlayment and below the shingles.

1.4 Asphalt ShinglesThe loss of roof covering during a hurricane is extremely common. There

are several different kinds of roof coverings available on the market today

including clay, concrete, and metal tile as well as wood shake and asphalt

shingles. This document does not address many of these varied roof coverings. Contact the manufacturers for details on adapting different

roofing materials to high wind areas. Asphalt shingles, the most common

material used today, are discussed in detail. Many of the asphalt shingles

made today are tested using a constant airflow of about 60 mph. A

Category I hurricane has a minimum 1-minute sustained wind of 74 mph.

Even strong windstorms can easily exceed 60 mph wind speed. The loss

of shingles during a storm poses two problems: the house is more

vulnerable to water damage and the lost shingles become wind-borne

projectiles, which can damage property. Asphalt shingles should only be

used on roof slopes of 2/12 or greater.

Materials

Asphalt shingles should have self-seal strips. Tab adhesives are designed

for local temperature extremes, so use local products appropriate for the

climate. Standard 3-tab asphalt shingles may be used with the application

requirements discussed in the following sections. Special high wind

shingles are also available which have been tested using a constant airflowof 110 miles per hour.

Layout

Begin by attaching a starter course consisting of the top half of a shingle

with the tabs cut off. The tab-less shingle strips are installed along the

lower edge of the roof sheathing.



Go to www.bluesky-

foundation.com for info on

viewing or buying a copy of:

Holding on to Your Roof

Part I: Retrofitting Your

Roof Sheathing Using

Adhesives

Part II: Retrofitting Your

Asphalt Shingle Roof

Covering and Sheathing

Connection.

Figure 1.8: Shingle Layout and Attachment

Attach starter strip with6 nails per strip 1/2” infrom edge of sheathing.See detail.

Starter strip oftrimmed shinglesoverhang 3/8” @eave & rake (tp.).

Do not invert.

Metal drip edge.

Remove tabs forstarter strips (typ.).

Remove 1/2 tab @rake starter strip.

Attach shingle with 6nails per shingle (seetypical asphaltshingle attachmentdetail).

Start first course withfull strip. Overhangshingles 3/8” @ eaveand rake (typ).

Start second course with full stripminus 1/2 tab.

Start third course with full stripminus first tab.

Place 2 dabs (about 1” in dia.)of roof cement per course @rake.

Place 2 dabs (about 1” in dia.) oroof cement on drip edge percourse @ rake.

Metal drip edge.

Place 3 dabs (about 1” in dia.) ofroof cement per tab betweenstarter strip and first course or2”x11” band of roof cement pertab.

Attachment

Figure 1.8 shows the attachment methods for standard, 3-tab asphalt

shingles; details are discussed below. High wind attachment

recommendations for special high wind shingles are provided by each

manufacturer and may be different from those discussed here.

The shingle strips in the starter course are attached with six nails perstrip, nailed 1/2” from the edge of the sheathing. Then three 1” diameter

dabs of roof cement per foot are applied between the starter strip and the

first course of shingles.

Nails must be galvanized or stainless steel, aluminum or copper with a

minimum 12 gage shank and minimum 3/8” diameter head. Nails must be

of sufficient length to penetrate through shingles, underlayment and

sheathing with an excess of 3/4”. There should be 6 nails per shingle

located halfway between the top of the cutout and the sealant strip. Nails

must be driven flush with the surface of the shingle.



For added protection hand-tab each shingle along any roof edge with

roofing adhesive. Securing the bottom edge of each shingle will give it a

greater chance of resisting the uplift forces created by a high wind event.

Venting

Venting systems should be designed to protect from wind-driven rains.

Gable end vents should be covered to protect against wind borne debris,with an approved shutter or cover tested to the standards discussed in

Chapter 2. All vents should also be well-attached to the roof, according

to manufacturer’s recommendations to resist high winds.



Retrofit Standards for Roof

Systems_______________________________________________________________________

1. A. Replace Roof Covering and Replace

SheathingRoof covering is to be removed to the decking level and all roof deck is to

be replaced in accordance with locally adopted building codes. Nailing of

sheathing shall follow guidelines given in Option 1.B below.Prior to the

application of underlayment, it is recommended that all joints between

structural sheathing panels be taped with a self-adhering polymer modified

bitumen sheet or rubberized asphalt underlayment that has a minimum

width of 6 inches. This self-adhering product shall be applied in accordance

with the manufacturers instructions for wood application. This product

shall have adherence strength suitable so that it remains attached to the

roof deck and provides secondary water resistance if the roof cover

underlayment tears or fails in a high wind event. Roof covering shall then

be installed in accordance with locally adopted building codes. For three-

tab composite asphalt shingles, 6 roofing nails are required for each shingle.

1. B. Replace Roof Covering and Re-nail

SheathingRoof covering is to be removed to the decking level. If no sheathing

panels need replacing, all roof sheathing is to be re-nailed such that

fastener spacing complies with Table 1.1 and local building codes.

Existing fasteners may be used to satisfy this requirement. It is

recommended re-nailing be done with 8d deformed (ring) shank nails.

Prior to the application of underlayment, it is recommended that all joint

between structural sheathing panels be taped with a self-adhering polymer

modified bitumen sheet or rubberized asphalt underlayment that has aminimum width of 6 inches. This self-adhering product shall be applied in

accordance with the manufacturers instructions for wood application.

This product shall have adherence strength suitable so that it remains

attached to the roof deck and provides secondary water resistance if the

roof cover underlayment tears or fails in a high wind event. Roof covering

shall then be installed according to locally adopted building codes. For

three-tab composite asphalt shingles, 6 roofing nails are required for each

shingle.



1. C. Replace Roof CoveringRoof covering is to be removed to the decking level. Prior to

underlayment application, if no sheathing panels need replacing and

nailing pattern is sufficient, it is recommended to tape all joins between

plywood sheets with a self-adhering polymer modified bitumen sheet or

rubberized asphalt underlayment that has a minimum width of 6 inches.

This self-adhering product shall be applied in accordance with the

manufacturers instructions for wood application. This product shall have

adherence strength suitable so that it remains attached to the roof deck

and provides secondary water resistance if the roof cover underlayment

tears or fails in a high wind event. All new coverings are to be installed in

accordance with locally adopted building codes. For three-tab composite

asphalt shingles, 6 nails are required for each shingle.

1. D. Apply Adhesive to Roof Decking andRaftersFor cases where the roof covering is adequate and attic access is available,

adhesive can be applied to the underside of the roof sheathing from the

attic such that a positive bond between the joists and the sheathing is

formed. The applied adhesive shall be AFG-O1 approved. Joints between

sheathing pieces shall also be caulked with adhesive to prevent water

infiltration in the event of roof covering losses. The adhesive shall be

applied continuously to the eaves. Commercially available urethane foamsystems may also be used according to manufacturer specifications for high

wind uplift resistance.



Chapter 2

Wall Systems



Wall Systems

Building codes categorize all residential buildings as enclosed, partially

enclosed or open. These classifications are the basis for the calculation of

the external and internal pressures on the building. Most buildings are

designed and built as enclosed structures. However, perforations in the

building envelope as small as 1 percent of the wall area can transform an

enclosed building to a partially enclosed building. This doubles the uplift

pressures on the roof and the outward pressures on walls.

Unprotected windows and doors can be penetrated easily by wind borne

debris in high winds, thus allowing entry of damaging water and wind.

Protecting openings with impact resistant components can prevent muchof this damage. All wall openings should be protected since winds can

emanate from any direction in a wind event.

2.1 WindowsAll windows greater than one square foot should comply with the most

recent version of ASTM E1996, SSTD-12 or Miami-Dade County proto-

col A201, or else be protected by shutters that comply with one of those

standards.

Care should be used in the design of combination windows (several

individual windows clustered together) so that the combination window

can resist the design pressure. This can be accomplished by the window

manufacturer using “structural” mullions between the individual window

units to transfer loading to the framing around the window opening or by

installing the individual window units with structural framing in between

each window unit. The second option also has the advantage of being

able to use a number of smaller shutters to protect the window unit.

Windows located in the garage that offer access to the main structure

should be considered exterior windows and protected accordingly.



Window Selection

Each window unit must be selected to resist the maximum positive and

negative pressures listed in Table 2.1. Note that the pressure on the

window increases when the window is located closer to the edge of the

structure.

Windows are given DP Ratings based on their capability to withstandpressure. A DP Rating of 25 indicates that the window can withstand a

pressure of 25 psf, positive or negative. When selecting a window, look

for a window with a DP Rating that matches or exceeds the design pres-

sure for the window’s location.

There are two mainapproaches to retrofitting

windows to improve their

impact resistance or

completely protect them

from debris and pressure

changes.

1. Impact-resistant glass

2. Shutter systems

Window Protection

Unprotected, standard glass windows present the most vulnerable opening

in a building’s envelope. They can be broken easily by flying debris or

destroyed by wind pressure. Once window glass fails, the subsequent

pressurization of the structure can cause total destruction of the house. If

the house withstands the wind pressure, the interior may still be lost dueto water damage. With the exception of impact-resistant polycarbonate

glazing or some laminated glass systems, all window glass, whether it is

annealed, tempered, wire reinforced or insulated, needs to be protected

during a high wind event. For a typical residential application, hurricane

window film is not sufficient protection. Films can prevent injury due to

flying glass, but offer no protection once the window is breached because

they do not help keep glass in the window frame—or the frame in the

house.

Table 2.1: Window Selection Guide

Source: Table based on the wind provisions in ASCE 7-98.

Window is considered to be in edge strip if any portion of window is located within 4' of edge of structure. This table is based on 140 mph 3-second gust wind speed and

Exposure B. For values for different wind speeds, see Appendix D.

Greater Than 30 feet andMean Roof Less Than or Equal to Less Than or Equal to

Height 30 feet 45 feet

All Interior Edge All Interior Edge

Zone Zones Zone Strip Zones Zone Strip

Design Pressure (psf)

Size of Door orWindow (sq ft) Pos (+) Neg (-) Neg (-) Pos (+) Neg (-) Neg (-)

0-25 45 -48 -54 50 -53 -60

25-50 43 -46 -51 48 -52 -5550-100 40 -43 -48 45 -51 -53

100-200 39 -43 -45 43 -48 -50200+ 39 -42 -41 43 -47 -48



during a storm. For example, if the shutters will cover windows on an

upper floor or in a hard-to-reach position, they should be operable from

the inside. Temporary shutters can be difficult and/or dangerous to install

on second floor windows or higher because they require the use of a ladder.

Permanent Shutters

Permanent shutters should be installed by trained individuals according tothe manufacturer’s specifications to ensure the shutters perform as de-

signed and tested. The most important factor to consider when choosing

a shutter system is its installation as an approved system. It should be

designed and tested for resistance to hurricane force wind loads and debris

impact. Shutters should be able to withstand both positive and negative

wind pressures.

Permanent shutters come in many types and styles, including Bahama,

rolling, accordion, and colonial. Location of the building, location of the

window, and cost are some of the factors to consider when choosing a

shutter style. Depending on the manufacturer, each of these shutter

systems may either close from the inside or the outside.

Many shutters on the market may NOT be designed for high winds and

the associated impacts. It is important to look for shutters that have been

designed and tested to high wind standards. All permanent shutters

should comply with the most recent version of ASTM E1996, SSTD-12 or Miami-Dade County protocol A201.

Bahama Shutters

Bahama shutters are attached directly

above the window with a top hinge.

Adjustable side arms allow the shutter

to be raised or lowered. When closed

at the bottom and latched, approved

shutters provide the necessary wind

and impact resistance. Bahama

shutters should be installed accord-

ing to manufacturer’s specifications.

Bahama shutters should not be used

for windows that open outwards.

Figure 2.2: Bahama Shutter



Colonial ShuttersColonial shutters are mounted at the sides of windows. It is important

that the shutters cover the entire window when closed. Because of this,

colonial shutters may not be a good choice for wide windows. When

closed and latched, approved shutters provide the necessary wind and

impact resistance. Colonial shutters should be installed according to

manufacturer’s specifications.

Accordion Shutters

Accordion shutter systems consist of folding interlocking blades. The

blades connect to each other vertically and travel along tracks located at

the top and the bottom of the window. Accordion shutters are designed

to cover large spans and retract for easy storage. When closed and

latched, approved shutters provide the necessary wind and impact resis-

tance. Accordion shutters should be installed according to manufacturer’s

specifications.

Figure 2.3: ColonialShutters

Figure 2.4: Accordion Shutter



Rolling Shutters

Rolling shutters consist of slats that glide up

and down on tracks at the side of each

window. When closed and latched, approved

shutters provide the necessary wind and

impact resistance. Rolling shutters should be

installed according to manufacturer’s specifi-cations.

Temporary Shutters

Temporary shutters can be put in place by the

owner in the event of a storm warning.

Shutters should be able to withstand both

positive and negative wind pressures. Ply-

wood shutters and storm panels are two

examples of temporary shutters.

Plywood Shutters

One of the least expensive solutions for protecting windows is to con-

struct plywood panels that can be installed when a storm warning is

issued. Although the plywood may not withstand as much impact as

other shutter options, they do minimize the size of the opening into the

home. The attachment of plywood shutters depends on the structural

framing material and the exterior finish of the house. The mountinghardware should be pre-installed around each window and each panel

should be labeled with its intended location to facilitate installation.

While plywood shutters offer the lowest cost protection, they are cumber-

some to store and carry. Often more than one person is required to install

them. The Engineered Wood Association (APA) has developed standard

designs of plywood shutters for masonry and wood construction. For some

spans, 2x4s may be needed to strengthen the panels. The recommenda-

tions of the APA should be followed to determine the thickness of the

plywood panels. FEMA has also developed several details for installation

of plywood shutters on wood frame as well as masonry walls. FEMA or

APA publications can be used for design and construction of plywood

shutters. Both of these organizations maintain web sites at www.fema.gov

and www.apawood.org, respectively.

Figure 2.5: Rolling Shutter



With many doors it may

be difficult to determine

the frame installation. If

possible, pry up a length of

door molding. If there is

concern or doubt about

the frame’s installation,

add screws around the

frame that are long enough

to penetrate to the framing members.

Hardware is another area

that can be retrofitted to

improve a door’s strength.

Storm Panels

In addition to plywood, other temporary shutter systems are available,

including steel and aluminum panels and clear polycarbonate panels. The

advantage that these systems have over plywood is that they are designed

specifically to withstand the impact forces of a high wind event. Usually

these panels are corrugated and come in standard widths, allowing them

to be joined together to cover wider openings. As with permanent shut-ters, the panel systems should be tested and rated by the strictest current

testing procedures.

Storm panels also may have an installation system that is quicker than

attaching plywood panels. Clear panels can be installed well in advance

of the storm’s approach and allow light to continue to come through the

windows while other preparations inside the house are being made.

In general, the same principles for the plywood systems apply to other

temporary panel products. They should meet the specific standards for

impact resistance, their mounting hardware should be installed well

before a storm’s impact and they should be labeled for each respective

opening.

2.2 Exterior DoorsThree items should be considered when installing doors: the door, the

frame and the hardware. All three items are important in maintaining

the strength of the entire door system. Failure of any one of these three

components would result in a breach of the building envelope and ensu-

ing damage to the residence.

Exterior doors must be strong enough to resist the wind loads and impact

loads of wind- borne debris or be protected with a panel or shutter system

Doors that open outward do not have the additional resistance to wind

suction provided by the doorjamb that inward opening doors have. Also,

hollow wood doors can fail under the wind and impact loads in a high

wind event. A secure lock set is also needed to help the door resist debris

impact.

Doors located in the garage that offer access to the main structure should

be considered exterior doors and protected accordingly.



Frames

The frames of all exterior doors must be mounted securely to the wall

systems. Additional fasteners can be added to strengthen frames as

needed. Frames that are attached improperly could fail in a hurricane and

allow wind and water penetration.

HardwareEvery door should have three four-inch screw hinges and a dead bolt

security lock with a minimum one inch bolt throw length. Screws used

for the hinges and the strike plate should extend into the framing

members, not just into the door frame. This is true for the dead bolt too.

The bolt throw should be long enough to extend to the framing members

not just into the door frame, which could split and fail in a storm.

The screws included with pre-hung doors should be replaced with screws

of sufficient length to extend into the framing members.

Double doors should have either surface or integral bolts installed that

secure the center of the doors to the header framing member and extend

into the subfloor. See Figure 2.6 below.

Figure 2.6: Door Hardware Illustration

The screw lengths and deadbolt throw should have been

measured during the house

inspection. If either item is

too short to extend through

the frame, they should be

replaced. Screws for the

hinges and strike plates can

be removed and replaced

with longer screws. The

dead bolt also can be

removed from the door and

replaced with a new dead

bolt with a longer throw.

The hole in the door frame

may have to be extended to

accommodate the longer

throw length.

These are small retrofits that

can increase the door’s

strength to withstand a

storm and any other

unwanted attempts to gain

entry to the home.

Retrofitting can be

completed by checking the

length of the bolts, replacing

them if necessary, and

extending the hole depth

through the door frame and/

or threshold.



To ensure that the frame is

fully installed, all mounting

holes should be used and the

condition of the original

fasteners should be checked.

If any mounting holes are

not used or if any of the

screws have deteriorated,

new screws should be

installed.

If the sliding glass doors are

protected by a shutter or a

panel, adding fasteners to

the frame may not benecessary.

Glass Doors

Glass doors should be protected by one of the systems discussed in the

Windows section. In addition, sliding doors should be mounted securely

in their frames so they cannot be pushed in or pulled out under high wind

loads. The frame itself should be attached securely to the wall so that it,

too, does not fail under load.

2.3 Garage DoorsGarage doors serve as additional points of failure and subsequent breaches

of the house envelope. Garage doors are vulnerable to high wind loads fo

two reasons - the relatively long span of opening that they cover and the

strength of the materials from which their systems are constructed. Many

garage doors are constructed from lightweight materials to reduce weight

and expense. Although their lighter weight makes them easier to raise

and lower, it also makes them less resistant to the wind and impact forces

of a hurricane.

Garage door assemblies have three major weaknesses:

1. Deflection under wind loads

2. Track strength and installation

3. Impact resistance

Unbraced garage doors can deflect under the loads applied by high winds.

Depending on whether the door is on the windward or leeward side of the

structure, it will experience positive or negative pressures, respectively.

These pressures will push and pull the door out of its track. If the door is

not braced to resist these deflections, it may fail and allow the pressuriza-

tion of the residence’s interior.

The track is the second system that can fail under a storm’s forces. A

lightweight or poorly anchored and braced track may torque and twist

from the wind force on the garage door. As the track is bent out of shape

and fails, the door glider wheels will pull out of the track and the door wil

collapse.

The last concern when addressing garage doors is impact resistance.

Many doors are not designed to withstand the impact of wind borne

debris created by a hurricane. If the garage door is perforated during a

storm, it may allow interior pressurization and water damage.



Choosing a Garage Door

Use a garage door that is designed specifically to withstand both the wind

load and impact forces of a high wind event. Garage door and tracks

should comply with the most recent version of ASTM E1996, SSTD-12

or Miami-Dade County protocol A201. Garage doors must be properly

installed to provide protection.

Protect The Opening

For additional protection, construct and install a protective panel system

that covers the garage door opening in the same manner that a shutter

covers a window. The construction of a garage shutter is identical to the

construction and installation for a window, however, the extra span needs

to be considered and supported as if it were a large window.

Brace The Garage Door

There are two options for bracing the garage door.

The first option is to attach horizontal wood or metal girts to the interior

surface. The bracing members should extend the length of the door. The

girts are attached to the vertical bracing of the garage door. This option

allows the garage door to remain functional and, therefore, constantly

braced.

The second option is to attach vertical wood or metal girts to the interior

Figure 2.7: Garage Door Bracing IllustrationCourtesy of American Red Cross and Federal Emergency Management Agency -

Against The Wind.



surface. The bracing members should start above the garage door and

continue down the door and into pre-drilled holes in the garage floor.

The girts are attached to the vertical bracing of the garage door. This

option renders the garage door inoperable and, therefore, bracing should

be put in place by the owner in the event of a storm warning.

Brace The FrameSeveral steps are required to strengthen and brace the garage door frame.

The first element to be considered is the track itself. The heavier the

gauge of the material from which the frame is constructed, the better. A

track with a greater cross-sectional area will resist twisting more than a

thinner track. A second strengthening element is a web brace on the

brackets that connect the track to the wall. Web braces can be welded to

these brackets or the brackets can be removed and replaced with brackets

that have integral web bracing. The last connection to be considered to

strengthen the frame is the attachment of the frame to the garage wall. If

the garage door opening is masonry or concrete, the brackets should be

installed with expansion anchors to resist pullout. An epoxy adhesive can

be used in addition to the expansion anchors to provide even greater

resistance. If the house is wood framed, the brackets should be attached

to the framing, not just to the interior surface material. In either case, the

bolts or screws should be sized according to the manufacturer’s recommen-

dations for the specific length and width of the garage door.

Connectors

Connectors are available from a variety of connector manufacturers and

there are a many types that can be used in different situations. Some of

the applications in this chapter may include the use of a variety of con-

nectors and anchor bolts. All connectors and anchor bolts shall be

installed in accordance with the manufacturers specifications and in

compliance with the locally adopted minimum building code. All connec

tors should be corrosion-resistant. See Table C in the Appendix for

recommendations.

Several retrofit optionsaddress these weaknesses:

1. Replace the garage door

system

2. Protect the opening

3. Brace the door

4. Brace the frame

The track thickness can

only be increased by

replacing the track.



Retrofit Standards for Wall

Systems_______________________________________________________________________

2. A. Install Code Compliant Shutters on

WindowsShutters must satisfy the impact resistance and pressure standards in

SSTD 12-97 of the Standard Building Code, ASTM E1886 and ASTM

E1996 or standards in the Miami-Dade Protocol A201. Shutters must be

installed as per the manufacturers specifications. Other requirements: If the

structure is equipped with shutter protection or the equivalent thereof, non-

compliance with the one of the above reference standards should be verified

before replacement with new products. The contractor will ensure that all local

codes, standards and requirements are met.

2. B. Replace Windows with Code

Compliant Impact Resistant ProductsExisting windows shall be replaced with units that satisfy the impact

resistance and pressure standards in SSTD 12-97 of the Standard Building

Code, ASTM E1886 and ASTM E1996 or standards in the Miami-Dade

Protocol A201. Windows must be installed as per the manufacturers

specifications. Other requirements: The contractor will ensure that all localcodes, standards and requirements are met.

2. C. Install Code Compliant Accordion

Storm Shutters on Sliding Glass DoorsProtection devices must meet impact resistance and pressure standards in


E1996 or standards in the Miami-Dade Protocol A201. All devices must

be installed according to the manufacturers instructions. Other require-ments: See other requirements for Retrofit 2.B. above.



2. D. Replace Sliding Glass Doors with

Code Compliant Impact Resistant

ProductsExisting sliding glass doors shall be replaced with units that meet impact

resistance and pressure standards in SSTD 12-97 of the Standard Building


Protocol A201 for both impact resistance and pressure requirements.

Sliding glass doors must be installed as per the manufacturers specifica-

tions. Other requirements: See other requirements for Retrofit 2.B. above.

2. E. Replace Garage Doors with Code

Compliant Impact Resistant ProductsProtection devices must meet impact resistance and pressure standards in


E1996 or standards in the Miami-Dade Protocol A201. All devices must

be installed according to the manufacturers instructions. Other require-

ments: See other requirements for Retrofit 2.B. above.

2. F. Reinforce Garage DoorsRetrofit existing garage door with a “post” system that can be locked

during severe storms and provides positive reinforcement against pressure

loads. Brace the garage door frame. Materials and methods used to

reinforce garage doors and frame shall be installed per the manufacturers

specifications and in compliance with the locally adopted minimum

building code.

2. G. Replace One Entry Door and Shutter

Remaining DoorsOne entry door shall be replaced with an impact resistant product meet-

ing impact resistance and pressure standards in SSTD 12-97 of the Stan-

dard Building Code, ASTM E1886 and ASTM E1996 or standards in the

Miami-Dade Protocol A201. All remaining entry doors shall be equipped

with code compliant shutter devices. All devices must be installed accord

ing to the manufacturers instructions. Other requirements: See other re-

quirements for Retrofit 2.B. above.



2. H. Replace all Entry Doors with Code

Compliant Impact Resistant ProductsExisting entry doors shall be replaced with units that meet impact resis-

tance and pressure standards in SSTD 12-97 of the Standard Building


Protocol A201. Entry doors must be installed as per the manufacturers

specifications. Other requirements: See other requirements for Retrofit 2.E.

above.



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Chapter 3

Light Framing



Light Framing

3.1 Roof Framing

The two most common roof styles are gable and hip. Gable roofs areusually easier and cheaper to construct than hip roofs. Hip roofs, how-

ever, do have an advantage. The area of highest pressure on a hip roof is

half that of a gable roof. This is because a hip roof is more aerodynamic.

A hip roof also provides diaphragm support at the top of the end wall,

making it much stronger than a gable end wall which has no lateral

support at the junction of the top of the end wall and the bottom of the

gable truss. This is a very weak condition as customarily built (platform

framing) and special provisions must be made for support or continuous

framing at that point.

Light-framed roofs may be rafter-joist or truss. The following recommen-

dations or roof systems include roofs for the main structures, porches and

other built-out rooms. The following recommendations for roof systems

include roofs for the main structures, porches and other built-out rooms.

Rafter-Joist

The maximum rafter spacing, for a rafter-joist roof, should be 24” o.c.

The end of each rafter or ceiling joist should have at least 1.5” of bearing

on wood or metal.

A ridge board or a ridge beam is required for connection of rafters to each

other at the roof ridge.

Figure 3.1 Gable Roof Figure 3.2 Hip Roof



For a roof slope of less than 3/12 (25%), a ridge beam should be used.

The ridge beam should be designed for the specific span and load of the

roof that is to be supported by the ridge beam. If the span is long, the

ridge beam can be designed to transfer load to intermediate columns

along its length. Figures 3.3a and 3.3b show two ways of connecting

rafters to the ridge beam.

Ridge boards should carry no load other than bearing. Ridge boards

should be a minimum 2” nominal thickness and no less in depth than the

depth cut of the rafter. Rafters should be placed directly opposite eachother and bear against the ridge board. Either ceiling joists or rafter ties

should be used with a ridge board and should be parallel to rafters. Ceil-

ing joists or rafter ties should be continuous or securely connected where

they meet over interior partitions and nailed to adjacent rafters to provide

a continuous tie across the building. In addition to the ceiling joists or

rafter ties, a 1”x 6” collar beam should be nailed in the upper third of the

roof to every third pair of rafters. If ceiling joists are not an option, such

as with cathedral ceilings, collar beams should be nailed in the upper

Figure 3.3a Rafter to Ridge Beam Bearing Connection

Figure 3.3b Rafter to Ridge Beam Hanger Connection



third of the roof to every pair of rafters. Metal straps are also available for

collar ties, and leave more head room on low-slope roofs.

Uplift connectors should be provided at rafter bearing to resist the uplift

loads in Table 3.1. Uplift connection may be from rafter to plate or from

rafter to stud. When the former method is used there should also be

adequate connection between the plate and the stud. Figure 3.6 illus-

trates the rafter to plate to stud connections for wood framing. Framinganchors designed to carry horizontal load may be substituted for toe nails.

If metal studs are used, substitute screws for nails as described in manufac-

tures instructions. In addition to uplift loads connections should be

capable of resisting 150 lbs of lateral load parallel and perpendicular to

the wall for roof members spaced 12” o.c., 200 lbs for roof members spaced

16” o.c., and 300 lbs for roof members spaced 24” o.c.

Figure 3.4 Ceiling Joist Detail

Figure 3.5 Rafter Tie Detail

Metal strapping used as collar

ties may be an excellent

option for retrofitting the roof

framing.



Figure 3.8 Valley Framing

Valley and Hip Framing

All valleys and hips should have rafters no less than two inches nominal

thickness and no less than the cut end of the rafter in depth. The hip and

valley rafters should be designed to carry and distribute the specific load a

that point or be supported at the ridge by a brace to a bearing partition.

Figure 3.7 Hip Framing



Trusses

The maximum spacing for a truss roof should be 24” o.c. Trusses should

be braced to prevent out-of-plane rotation and provide lateral stability.

Trusses should not be notched, drilled, cut, spliced, or otherwise altered in

any manner without approval of the truss designer.

Uplift connectors should be provided at truss bearing to resist the upliftloads in Table 3.1. Uplift connections can be from truss to plate or truss to

stud. Figure 3.9 illustrates the truss to plate to stud connections for wooden

framing. If metal studs are used substitute screws for nails as described in

manufactures instructions. In addition to uplift loads connections should be

capable of resisting 150 lbs of lateral load parallel and perpendicular to the

wall for roof members spaced 12” o.c., 200 lbs for roof members spaced 16”

o.c., and 300 lbs for roof members spaced 24” o.c.

Valley and Hip Roofing

Where trusses are used to form a hip roof, a step-down hip system should

be used as shown in Figure 3.10. Uplift connections at bearing of hip

trusses should be determined using Table 3.2. This method is for a step-

down hip system only.

Figure 3.9 Various Truss toPlate, Truss to Stud, and

Plate to Stud Connections



Hip Truss From Table 3.1- 7' Endjack 11' EndjackMember Find Uplift System System

Load for: Multiply Uplift Load By

Endjacks 24' Building Width 0.68 0.68

Cornerjacks 24' Building Width 0.75 0.85

Hipjack 24' Building Width 1 1.1

with Trusses @ 24" o.c.

#1 Hip Truss Actual Building Width 1.8 2

with Trusses @ 24" o.c.

Source: 1999 SBCCI.

Table 3.2 Uplift Loads at Bearing for Step-Down Hip

Roof Systems

Figure 3.10 Hip Roof Framing with Trusses



Double Header Double

TrimmerRafter

Rafter

Double Header

Framing of Roof Openings

Openings in roof and ceiling framing should be framed with header and

trimmer joists. See Figure 3.11.

Figure 3.11 Framing of Roof Openings

For a header span of 4' or less, the header may be a single member the

same size as the rafter. A single trimmer rafter may be used to carry a

single header that is located within 3' of the trimmer rafter bearing. For a

header span greater than 4', the trimmer rafters and the header should be

doubled and of sufficient cross section to support the rafter framing into

the header. When the header span exceeds 6', approved hangers should

be used for the header to trimmer rafter connections. Tail rafters over 12'

long should be supported at the header by framing anchors or on ledger

strips no less than nominal 2" x 2".

Truss or Rafter To Wall Connection

The connection of the roof assembly to the exterior walls is extremely

important. If the wind is able to produce enough uplift on the roof, it can

pull the roof off the house. Roof framing members can consist of pre-

engineered roof trusses and/or common framed members. All roof-fram-

ing members should be secured to the walls by hurricane clips and/or

straps. A continuous load path should be provided to transmit the uplift

forces from the rafter or truss ties to the foundation.

There are several manufacturers of hurricane clips and straps and each

manufacturer has several products that are available to fit most condi-

tions. It is important to select the clips or straps with maximum uplift

and shear capacities that are available. All clips and straps should be




The intersection of the top of the wall and the roof are covered on the interior of

the building by the wall finish and on the exterior by the soffit assembly. This

makes retrofitting the roof-to-wall connection difficult. There are three

approaches to gain access to add hurricane straps to the roof/wall intersection.

Potentially several different products can be used. Each manufacturer can offer

technical information on uplift load resistance and recommend which products

are suitable for retrofit. For retrofitting in tight areas, screws may be used in place of nails, according to strap manufacturer’s instructions. Short nails made

for connectors are easier to install when retrofitting and help prevent bent nails

in connectors.

Retrofit Techniques and Products - Clips and Straps

There are three possible ways to gain access to the intersection of the roof to the

wall: from the interior, from the exterior, and during re-roofing.

From The InteriorOne solution is to remove the covering materials around the top of the interior

walls and ceiling. This process will provide access to the trusses and the top

plate of the wall. The expense of this technique is depends on the type of interior

finish. Some interior finishes such as plaster or wall papered walls may be too

expensive, invasive and time consuming to consider making holes in these walls

and then repairing after the retrofit is complete. If the interior is wood panels or

drywall, however, it may be more economical to remove these materials to gain

access to the top of the wall, install the retrofit and repair the access point.

From The Exterior

Access to roof members and top of the wall also may be gained from the

exterior. An examination of the soffit and exterior cladding must be made to

determine the cost, invasiveness and time to complete the retrofit. It may be as

simple as removing the soffit material to gain access, make the retrofit and

replace the soffit. In other cases, some access points may have to be cut through

cladding or cladding material may have to be removed and replaced once the

retrofit is accomplished.

During Re-Roof

When the sheathing is removed there is greater access to all components of the

roof load path. It also is easier to install a greater variety of clips or straps than

what the limited access of the attic or soffit may allow. This greater access offers

an opportunity to examine the condition of any existing connectors that may be

present. If any of these components appear corroded, damaged or incorrectly

installed, they should be replaced at this time.



compliance with the locally adopted minimum building code. See Figure

3.9 for some examples of clips and straps.

Gable End Bracing

Another major failure point is the collapse of the gable end. If gable-end

framing has not been sufficiently braced during construction it can deflect

and possibly fail under the strong inward and outward pressures thathurricane winds induce on a house. The collapse a gable end allows

internal pressurization. Wind and water damage may occur once the

building envelope has been breached. Figure 3.12 shows detail on bracing

a gable end wall.

Installing Bracing at Bottom of the Gable End

The forces produced by a hurricane on the gable ends can push or pull

until the deflection causes failure. Bracing the bottom of the truss to the

interior framing members gives the gable end increased strength to resist

the inward and outward forces that the winds apply.

To brace the bottom of the gable end, 2x4 members with a minimum

length of 8’ are installed perpendicular to the plane of the gable end at 6'

o.c. These bracing members should be connected to the bottom chord of

the gable end or to the base of the studs of the gable end with metal

connectors and fastened to each of the interior framing members they

intersect - either the bottom chords of the interior trusses or other fram-ing members. These connections should be made with a minimum of two

16d nails at each intersection.

Retrofit Techniques

and Products - Gable

End BracingThree retrofits have been

designed to prevent gable

end failure:

1. Installing bracing at

the bottom of the gable

end

2. Installing bracing

along the top edge of

the gable end

3. Strengthening the

connection between the

bottom of the gable end

and the top of the

sidewall

Bracing at the bottom of

the gable end is a retrofitthat provides effective

protection against

collapse. The top of the

gable end is braced by the

sheathing, assuming that it

is well connected, but the

bottom of the gable end

may be unbraced. This

lack of bracing would

make it quite vulnerable to

failure.

Figure 3.12 Roof Sheathing Layout and Endwall Bracing.

Rafter/Truss

Building Length

Sheathing

Blocking @

48” o.c. max.in first two

framingspaces at

each end



Installing Bracing Along the Top Edge of the

Gable End

Bracing at the top of the gable end can be achieved in two ways. One

method is to use the same technique as above. That is, installing 8' long

2x4 members at 6' o.c. perpendicular to the gable end surface.

Another method is to install 2x4 blocking at 24" o.c. between the gableend framing and first two interior rafters or truss top chords. The concept

behind this more limited approach is that the roof sheathing will provide

most of the support and connection along the top of the gable end and

the two layers of blocking will reinforce this support.

Connecting the Bottom of the Gable End to the Top

of the End Wall

The bottom chord of the gable-end truss should be attached securely to

the top plate below it; there should be no visible gaps. A pair of nails, a

minimum of 10d for wood framing, should be toenailed on each side 24"

o.c. to create a solid connection between the truss and the top plate. For

metal framing replace the 10d nails with #8 screws. This connection will

reduce the deflection and possibility of failure of the gable end wall during

a hurricane.

Lookout Gable End Overhangs

It is a common building practice to construct the framing for the over-hang at a gable end on the ground and to tack it in place at the roof

eaves. This overhang commonly is referred to as ladder framed because

the framing looks like a ladder before it is attached to the house (see Figure

3.13). Although, this is an economical method of constructing an over-

hang, it is a poor design in terms of wind resistance. The attachment of

the ladder frame to the house is weak. It is designed to resist the gravity

loads that it constantly experiences, but it is not designed to resist the

uplift forces of a hurricane. Hurricane-force winds can push up the

overhangs and pry the sheathing loose along the edge. Once the sheath-

ing along the edge is gone, the entire roof is at risk.

One solution to this problem is to add new lookouts to create the over-

hang using 2x6 members (see Figure 3.14). The new 2x6 members are

placed at 2’ o.c. with the 6” face parallel to the sheathing surface. They

extend from the second framing member, across the gable end member,

and project out the distance of the overhang. To maintain the level of

The last important area to

retrofit at the gable ends is

the connection between the

gable- end trusses and the

top plate of the end wall

below. This is a quick and

easy retrofit that requiresonly a hammer and nails.

This connection also can be

made using hurricane clips

or straps to secure the truss

to the wall top plate. Clips

or straps can be used on

both masonry and wood

frame construction. Check

with the manufacturer of

the chosen connector to

recommend the appropriate

product and installation

methods.



the roof, the roof framing members must be notched to accept the lookou

members. Since most building codes forbid cutting into the depth of a

framing member in the middle third of its span, a 2x4 should be attached

to the second rafter or the truss. This additional 2x4 is attached only to

the second roof framing element.

Connectors


there are a many types that can be used in different situations. Some of

the applications in this chapter may include the use of a variety of con-

nectors and anchor bolts. All connectors and anchor bolts should be


compliance with the locally adopted minimum building code. All con-

nectors should be corrosion-resistant. See Table C in the Appendix for

recommendations.

During re-roofing, the

sheathing along the gable

edge can be removed and

2x6 members can be

retrofitted to create the

overhang.

Figure 3.13 Ladder Framing for Overhang

Lookout Block

Gable End Truss or Endwall

Section A-A



Lesser ofL/2 or 2’

RequiredBlocking

Minimum 2x4 Outlooker

Gable Endwall

Section A-A

Figure 3.14 Lookout Framing for Overhang

3.2 Wall FramingWall studs should be continuous between horizontal supports (floor,

ceiling or roof diaphragms). If platform construction is used on a gable

endwall, the ceiling diaphragm must have adequate strength and stiffness

to brace the gable endwall against out-of-plane loads at the platform level

If there is not a ceiling diaphragm (cathedral ceiling or open floor plan

with two-story walls), balloon framing should be used with the wall studs

spanning the full height of the walls.

Studs should be selected in accordance with Table 3.3. Studs should be

continuous between horizontal supports. A minimum of three studs

should be provided at each corner in an exterior wall.



Table 3.3 Stud Selection

Nominal Stud Sizes

2 x 4 2 x 6 2 x 8

Stud Length Stud Spacing(ft) (in)

12 1312 531 306

8 16 1749 708 408

24 2623 1062 611

12 1982 803 462

10 16 2643 1070 616

24 3965 1605 924

12 2767 1120 645

12 16 3689 1494 86024 5533 2241 1290

12 3658 1481 852

14 16 4877 1975 1137

24 — 2962 1705

12 4650 1883 1084

16 16 — 2511 1445

24 — 3766 2167

12 5737 2323 1337

18 16 — 3098 178324 — 4647 2674

12 — 2801 1612

20 16 — 3735 2149

24 — 5602 3224

Source: 2001 Wood Frame Construction Manual.Tabulated bending stresses assume a building located in Exposure B with a mean roof height of 33 feet. All values are based on a 140 mph 3-second gust wind speed. For different wind

speeds see Appendix Table F. For Fb values of various wood species and grades, see the 2001

Wood Frame Construction Manual Supplement, Table 4A.

Minimum Fb Required (psi)

Wood stud walls should be capped with a double top plate installed to

provide overlapping at corners and intersections with bearing partitions.

End joints in top plates should be offset at least 24”. Wall studs should

have full bearing on at least one bottom plate no less 2” nominal thick-

ness and no less than the width of wall studs. Bottom plates connected to

the foundation should have full bearing on the foundation.

Wall Bracing

Wood structural panel sheathing at least 5/16” thick for 16” stud spacing

and at least 3/8” thick for 24” stud spacing is attached using 8d common



The retrofit options for this

section include installing

connectors that tie the wall

framing to the floor system.

Connectors can be found from

a variety of connector manu-

facturers and there are a

multitude of types that can be

used in different situations.

Retrofitting the wall framing to

floor system can include adding

new anchor bolts or connectors

and can require removing a

portion of the wall covering.

Whether to approach the problem from the inside or the

outside depends on the situation

present. All anchors and

connectors should be installed

in accordance with the manu-

facturers specifications.

When dealing with slab on

grade systems with wood

walls, holes should be drilled

through the wall’s existing

bottom plate into the concrete

foundation and properly sized

approved anchor bolts should

be installed at intervals that

comply with the locally

adopted minimum building code. A commercial grade

epoxy may be used to install

the anchor bolts. The most

common anchoring system for

wood walls and wood floor

systems is the use of metal

straps or connectors.

nails spaced 6” o.c. at edges and 12” o.c. at intermediate supports. Each

wall panel should be at least 4’ in length and attached to a minimum of four studs when studs are spaced at 16” and a minimum of three studs

when studs are space at 24”. All vertical joints of panel sheathing should

occur over studs. Horizontal joints should occur over blocking of a mini-

mum 11/2” thickness. When metal studs are used, the wood structural

sheathing panels should be a minimum of 19/32” for 24” stud spacing.

Wall Openings

Headers should be provided over all exterior wall openings and should be

supported by wall studs, jack studs, hangers, or framing anchors. Figure

3.15 illustrates the stud and header details around a wall opening for wood

framing.

Detailed information for header spans for exterior load bearing walls can

be found in Tables 3.22A-3.22F in the 2001 Wood Frame Construction

Manual. These tables provide the maximum header/girder spans for

Table 3.4 Maximum Stud Spacing

Stud Size (in)

2 x 3 2x4 2 x 5 2 x 6 2 x 8Maximum Unsupported Stud Length (ft)

- 10 10 10 10

Load bearing Studs

Supporting Maximum Stud Spacing (inches o.c.)

Roof & Ceiling Only - 24 24 24 24

1 Floor Only - 24 24 24 24

Roof, Ceiling, & 1

Floor Only - 16 16 24 24

2 Floors Only - 16 16 24 24

Roof, Ceiling, & 2Floors - - - 16 24

Maximum Unsupported Stud Length (ft)

Non-loadbearing 10 14 16 20 20

Studs Maximum Stud Spacing (inches o.c.)

16 24 24 24 24

Source: 2001 Wood Frame Construction Manual.



Figure 3.15 Studs and Headers

around Wall Openings

common lumber species and stud sizes based on what is being supported(one-story, two-stories, etc.) and the dead and live loads. Table 3.22F also

gives the number of jack studs required at each end of the header.

Wall to Foundation Connection

The wall is attached to a sill or bottom plate which is then anchored to

the foundation. The bottom plate should not be less than 2 inch normal

thickness and no less than the width of the wall studs. The bottom plate

transfers the lateral loads to the floor to the foundation.

The various connections between the walls and the foundation are illus-

trated in the figures that follow.

Figure 3.16 Bottom Plate to Slab on Grade



Figure 3.18 Wall to Pile Foundation

Figure 3.19 Sill Plate to Concrete Foundation Wall

Figure 3.20 Sill Plate to Masonry Foundation Wall

Figure 3.17 Wall to Permanent Wood Foundation



3.3 FoundationsThe two primary types of floor systems found in residential construction

are concrete and off grade wood floors or a combination of the two.

Connections between the floor system and the foundation system are

important for maintaining the integrity of entire structure from the

ground up. These connections help resist wind forces from tropical

storms, hurricanes or hydrostatic forces from floods and storm surge.

Structures with floor systems not properly connected to the foundation

can be lifted off their foundations and result in extensive damage or total

destruction.

There are many types of foundations used in the construction of residen-

tial structures including concrete slab on grade, concrete footings and

stem walls, piers and piles to name a few. Foundations should be con-

structed on clean compacted fill and should comply with design standardsof the locally adopted minimum building code. Foundation systems

should be connected to the floor system with approved connectors and

installed in compliance with the manufacturers specifications.

Slab-on-Grade Foundations and Footings

Concrete slabs and footings should be poured as a monolithic unit. The

minimum monolithic footing size is 20” thick by 12” wide for one story

buildings and 20” thick by 16” wide for two story buildings. The thickness

includes the thickness of the slab. Either footing size should be reinforced

with two continuous #5 bars.

Wall bottom plates should be anchored to the foundation system with

anchor bolts having a minimum bolt of 5/8” and 3” x 3” x 1/8” washers

spaced 1.5’ o.c. Anchor bolts should be embedded a minimum of 7” in

the bond beam and within 6”-12” of corners and plate ends.

Footings should be level or stepped so that both top and bottom of the

footings are level. The bottom of all footings except for monolithic slab-on-

grade interior footings, should be no less than 12” below finished ground

line. All footings, except for monolithic slab-on-grade foundations, should

be at least 4” wider on each side than the wall resting on the footing.

Floor System to Foundation Connections

The connection between the floor system and the foundation acts to

anchor the house to the earth. This connection completes the load path

To retrofit this connection

properly, it is necessary to

evaluate the anchoring

system used to connect the

floor to the foundation.



from the roof to the earth resisting wind and hydrostatic loads that can

impact the structure. A failure at this connection will compromise the

integrity of the entire building. The most common anchoring system for

wood floor systems is the use of metal straps or connectors. Approved

connectors should be installed in compliance with the locally adopted

minimum building code and in accordance with the manufacturer’s

specifications. Uplift connectors should be provided at every full lengthstud and be continuous from the exterior wall into the foundation wall.

Piers and Stemwalls

Where spot piers are used, spacing should not exceed 8 feet o.c. unless

engineering analysis indicates a greater spacing is acceptable. Piers should

be properly anchored to resist overturning and sliding. Sills used in

conjunction with piers and stemwalls should consist of approved wood of

natural decay resistance or preservative-treated wood. Sill plates should

be anchored to the foundation system with anchor bolts having a mini-

mum bolt diameter of 5/8” and 3”x3”x1/8” washers spaced 4’ o.c. Anchor

bolts should be embedded a minimum of 7” in the bond beam and within

6”-12” of corners and plate ends.

Footings for stemwalls where soil capacity is greater than 2000 psf should

be at least 20” wide by 10” thick and be reinforced with two No. 5 con-

tinuous bars. (If the capacity is less than 2000 psf, an engineer will need

to design the foundation/footing.) The thickness includes the thickness othe slab. Standard 5/8” diameter, 90o hooked footing dowels should be

embedded a minimum of 6” and spaced 8’ o.c. and within 2’ of corners.

Exterior foundation walls should extend no higher than 3’ above finished

grade and be constructed with a least 8” concrete masonry units, 6”

hollow clay brick, 3” solid clay brick, or 4” hollow concrete masonry

units.

Piles

The most common type of pile foundation is the elevated wood pile

foundation, in which the tops of the piles extend above grade to the level

of the design flood elevation. For maximum effectiveness piles should be

inserted into the ground using a pile driver.

Embedment depth of piles is important. Shallow or small-dimensioned

piles may need bracing to provide lateral stability in all directions.

Bracing methods should be approved by the local building official. Well-



embedded and adequately dimensioned piles may not need bracing– see

local codes. Pile to girder connections can be strengthened using metal

strap connections. Spacing of the straps should comply with local codes.

Corrosion-resistant materials should be used as appropriate; see Appendix

Table C for recommendations.

ConnectorsConnectors can be found from a variety of connector manufacturers and

there are a multitude of types that can be used in different situations. The

use of stainless steel connectors is highly recommended in coastal areas, as

galvanized connectors will rust over time and will need to be replaced

periodically. All connectors and anchor bolts should be installed in

accordance with the manufacturer’s specifications and in compliance with

the locally adopted minimum building code.



Retrofit Standards for Floor

and Foundation Systems

_______________________________________________________________________

3. A. Install Code Compliant AnchoringSystem For Wall to Floor or Wall to

Foundation ConnectionInstall connectors from the wall system to the floor or to the foundation.

Connectors used in anchoring the wall system must satisfy the require-

ments of the locally adopted building code and shall be installed as per

the manufacturers specifications.

3. B. Install Code Compliant AnchoringSystem for Floor to Foundation

ConnectionInstall connectors from the floor system to the foundation. Connectors

used in anchoring the floor system must satisfy the requirements of the

locally adopted building code and shall be installed as per the manufactur

ers specifications. Sills that may have to be replaced during this retrofit

must be replaced with materials of approved wood of natural decay resis-

tance or preservative-treated wood.

3. C. Brace PilesInstall braces on shallow or small-dimensioned piles to provide lateral

stability in all directions. Methods and materials used to brace piles shall

comply with locally adopted building code and shall be installed

according to manufacturer’s specifications.

3. D. Install Code Compliant AnchoringSystem for Girder ConnectionInstall connectors from the girder to piles, piers or stem walls. Connec-

tors used in anchoring the girder must satisfy the requirements of the

locally adopted building code and shall be installed as per the manufactur

ers specifications.



Chapter 4

Concrete and Masonry



Concrete and Masonry

This chapter deals with concrete and masonry foundations and masonry

walls. For this chapter all of the roof to wall connections are for a light

framing roof system connected to a masonry wall.

4.1 Roof FramingConcrete and masonry construction generally uses the light framing

roofing system described in detail in Section 3.1.

Uplift connectors should be provided at rafter bearing to resist the uplift

loads in Table 3.1. Uplift connection may be from truss/rafter to bond

beam or from truss/rafter to nailer. When the latter method is used there

should also be adequate connection between the nailer and the masonry

wall. Figure 4.1 illustrates the truss/rafter to nailer to masonry wall con-

nections. In addition to uplift loads connections should be capable of

resisting 150 lbs of lateral load parallel and perpendicular to the wall for

roof members spaced 12" o.c., 200 lbs for roof members spaced 16" o.c.,and 300 lbs for roof members spaced 24" o.c.

Figure 4.1 Roof to Concrete orMasonry Sidewall Connection



Gable End Bracing

For masonry wall construction below the gable-end, the same methods as

in Chapter 3 can be completed using bolts instead of nails.

For concrete or masonry walls carried to full roof height, a cast-in-place

rake beam with a 4” or more dimension measured perpendicular to the

slope and one # 5 continuous reinforcing bar should be cast along the rooline (see Figure 4.2). A minimum 2 x 4 wood nailer should be bolted to

the rake beam to connect the wall to roof sheathing.

Connectors


there are many types that can be used in different situations. Some of the

applications in this chapter may include the use of a variety of connectors

and anchor bolts. All connectors and anchor bolts should be installed inaccordance with the manufacturers specifications and in compliance with

the locally adopted minimum building code. All connectors should be

corrosion-resistant. See Table C in the Appendix for corrosion resistance

recommendations.

Figure 4.2 Continuous Gable Endwall Reinforcement

If retrofitting, masonry

screws (tapcons) can beused in place of nails assuggested in Chapter 3.

Masonry screws and thespecial bits for drilling the pilot holes are available atmost hardware stores andhome supply centers.

Another alternative is to useretrofit bolts. These boltsare pre-cut threaded rods,supplied with a nut andwasher. A 1 / 2 ” diameter,6" length of retrofit bolt canbe installed every 4’ o.c. Toinstall these bolts, drill a 5 / 8“ diameter hole and remove

the dust from the hole. If the dust is not removed, itwill reduce the epoxy’sholding capacity. Fill thehole halfway with epoxy,starting at the bottom toavoid air pockets. Insert the

bolt, turning it slowly untilit reaches the bottom of thehole.

This connection also can bemade using hurricane clipsor straps to secure the trussto the wall top plate. Clipsor straps can be used onboth masonry and wood

frame construction. Check

with the manufacturer of the chosen connector torecommend the appropriate product and installationmethods.



To retrofit this connection properly, it is necessary toevaluate the anchoring

system used to connect the floor to the foundation.

4.2 Masonry Wall ConnectionExterior concrete and masonry walls should be no less than 8” thick for

high wind regions. Six-inch walls are permitted for one story buildings up

to a maximum ceiling height of 10’ and for the top story of a multistory

building where that story has a maximum ceiling height of 8’. Masonry

walls should include one #5 bar in an 8-inch bond beam at all floor and

roof levels and one #5 bar as vertical reinforcement in a grouted cell at all

corners and spaced at a maximum of 16 ft intervals in exterior walls.

However, the spacing may need to be reduced to as small as 4 ft intervals

based on the building dimensions.

Wall Openings

In addition to the reinforcing above and below a wall opening, reinforcing

may be required on each side of an opening in a masonry wall. One #5

bar should be placed on each side of openings 1' or wider in concrete

walls, and 6' or wider in masonry walls. For openings in masonry walls

wider than 12', two #5 or one #7 bar is required.

4.3 FoundationsThe two primary types of floor systems found in residential construction

are concrete and off grade wood floors or a combination of the two.

Connections between the floor system and the foundation system are

important for maintaining the integrity of entire structure from the

ground up. These connections help resist wind forces from tropical storms

hurricanes or hydrostatic forces from floods and storm surge. Structures

with floor systems not properly connected to the foundation can be lifted

off their foundations and result in extensive damage or total destruction.

The types of foundations used in the construction of concrete and

masonry residential structures include concrete slab-on-grade, concrete

footings and stemwalls. Foundations should be constructed on clean

compacted fill and should comply with design standards of the locallyadopted minimum building code. Foundation systems should be

connected to the floor system with approved connectors and installed in

compliance with the manufacturers specifications.

Slab-on-Grade Foundations and Footings

Slab-on-grade foundations should be monolithic with two #5 continuous

horizontal reinforcing bars. Dimensions are 20” in height including the

slab thickness and 12” wide for one story and 16” wide for two stories.



Footings should be level or stepped so that both top and bottom of the

footings are level. The bottom of all footings, except for monolithic slab-

on-grade interior footings, should be no less than 12" below finished

ground line. All footings, except for monolithic slab- on-grade

foundations, should be at least 4" wider on each side than the wall resting

on the footing. Footing dowel bars should be #5, have a standard 90o

hook, and be embedded 5" into 8" footings and at least 6" into all otherfootings.

Floor System to Foundation Connections

The connection between the floor system and the foundation acts to anchor

the house to the earth. This connection completes the load path from the

roof to the earth resisting wind and hydrostatic loads that can impact the

structure. A failure at this connection will compromise the integrity of the

entire building. The most common anchoring system for wood floor systems i

the use of metal straps or connectors. Approved connectors should be

installed in compliance with the locally adopted minimum building code and

in accordance with the manufacturer’s specifications.

Uplift connectors should be provided at every full length stud and be

continuous from the exterior wall into the foundation wall.

Stemwalls

Foundation stemwalls should be as thick or thicker than the wall

supported, but never less than 8" thick in any case. Each stemwall should

have the same reinforcing as the wall above. Stemwalls should not extend

more than 3' above finished grade.

Footings for stemwalls should be at least 20" wide by 10" thick and be

reinforced with two No.5 continuous bars. The thickness includes the

thickness of the slab.

ConnectorsConnectors can be found from a variety of connector manufacturers and

there are a multitude of types that can be used in different situations. All

connectors should be corrosion resistant. See Appendix Table C for

recommendations. All connectors and anchor bolts should be installed in

accordance with the manufacturer’s specifications and in compliance with

the locally adopted minimum building code.



Retrofit Standards for Floor

and Foundation Systems

_______________________________________________________________________

4.A Install Code Complaint AnchoringSystem for Wall to Floor or Wall to

Foundation ConnectionInstall connectors from the wall system to the floor or to the foundation.Connectors used in anchoring the wall system must satisfy the require-ments of the locally adopted building code and shall be installed as perthe manufacturers specifications.

4.B Install Code Complaint Anchoring

System for Floor to FoundationConnectionInstall connectors from the floor system to the foundation. Connectorsused in anchoring the floor system must satisfy the requirements of thelocally adopted building code and shall be installed as per the manufacturers specifications. Sills that may have to be replaced during this retrofit

must be replaced with materials of approved wood of natural decay resis-tance or preservative-treated wood.

4.C Install Code Complaint Anchoring

System for Girder ConnectionInstall connectors from the girder to piles, piers or stem walls. Connectorsused in anchoring the girder must satisfy the requirements of the locally

adopted building code and shall be installed as per the manufacturersspecifications.



Appendix

Table A: Minimum Roof Sheathing Panel Thickness

3 Second Gust Speed (mph)

90 100 110 120 130Rafter/Truss Spacing

(inches o.c.) Roof SheathingMinimum Panel Thickness

12 3/8" 3/8" 3/8" 3/8" 3/8"

16 3/8" 3/8" 3/8" 3/8" 3/8"

19.2 3/8" 3/8" 3/8" 3/8" 3/8"

24 3/8" 3/8" 3/8" 7/16" 7/16"


-

Southern Yellow Pine (SP) G

3 second Gust Speed (mph)

90 100 110 120 130

Maximum Nail Spacing (inches o.c.)SheathingLocation

Rafter/TrussSpacing

(inches o.c.)

E I E I E I E I E I

12 6 12 6 12 6 12 6 12 6 12

16 6 12 6 12 6 12 6 12 6 6

19.2 6 12 6 12 6 12 6 12 6 6

4' PerimeterEdge Zone

24 6 12 6 6 6 12 6 12 6 6

12 6 12 6 12 6 12 6 12 6 12

16 6 12 6 12 6 12 6 12 6 12

19.2 6 12 6 12 6 12 6 12 6 12Interior Zone

24 6 12 6 12 6 12 6 12 6 12

Table B.1: Roof Sheathing Nailing Schedule: Southern Yellow Pine


E = Nail spacing at panel edges.I = Nail spacing at intermediate supports in the panel field.

-



Spruce Pine Fir (SPF) G<0.49

3 second Gust Speed (mph)

90 100 110 120 130

Maximum Nail Spacing (inches o.c.)SheathingLocation

Rafter/Truss

Spacing(inches o.c.)

E I E I E I E I E I

12 6 12 6 6 6 6 6 6 6 6

16 6 12 6 6 6 6 6 6 6 6

19.2 6 6 6 6 6 6 6 6 4 4

4' PerimeterEdge Zone

24 6 6 6 6 4 4 4 4 4 4

12 6 12 6 12 6 12 6 12 6 4

16 6 12 6 12 6 12 6 12 6 4

19.2 6 12 6 12 6 12 6 12 6 4Interior Zone

24 6 12 6 12 6 12 6 12 6 4

Table B.2: Roof Sheathing Nailing Schedule: Spruce Pine Fir

Source: 2001 Wood Frame Construction Manual.E = Nail spacing at panel edges.

I = Nail spacing at intermediate supports in the panel field.



Recommendations for Corrosion-Resistant Materials and Methods* Source: FEMA TB 8-96

Location

Class of exposure**

Oceanfront Buildings

(300 feet or less from the

shoreline)***

Intermediate Rows of

Buildings in Corrosion-

Prone Areas

(300 to 3,000 feet from the

shoreline)***

Buildings Farther

Landward

(Greater than 3,000 feet

from the shoreline)***

Partially shelteredexteriors

1. Avoid sheetmetalconnectors wherepossible.

2. Use stainless steelconnectors.

3. Use connectors withthicker galvanizingand replace themwhen necessary.

Use connectors withthicker galvanizing.(Optional: stainlesssteel)

Use connectors withstandard galvanizing.(Optional: thickergalvanizing)

Boldly exposed exteriors 1. Avoid sheetmetalconnectors wherepossible.

2. Use stainless steelconnectors.

3. Use connectors withthicker galvanizingand replace themwhen necessary.

Use connectors withthicker galvanizing.(Optional: stainlesssteel)


Vented Enclosurs 1. Use connectors withthicker galvanizing.(Optional: stainlesssteel)

2. Use TPI paints ontruss plates.

(Optional for trussplates: thickergalvanizing, TPI paintsover thicker galvanizing,or stainless steel)

1. Use connectors withthicker galvanizingnear vents.

2. Use TPI paints ontruss plates nearvents.

(Optional: thickergalvanizing for allconnectors)


Interior living space Use connectors withstandard galvanizing.(Optional: thickergalvanizing)



* Recommendations are based on the available research and are subject to change in future Technical

Bulletins.

** see Figure 5 in FEMA's TB 8-96 for corrosion classes.

*** Distances may vary considerably depending on local climate. The width of the corrosion hazard area

relative to the ocean should be determined in each community from field observations and any existing

corrosion studies.

Table C: Corrosion

Care should also be taken to ensure that connectors and fasteners used near salt water are

corrosion-resistant. The Federal Emergency Management Agency (FEMA) has adocument, TB 8-96: Corrosion Protection for Metal Connectors in Coastal Areas, that

discusses corrosion resistance in detail; recommendations are summarized below.

Note: To obtain the FEMA document, call 800/480-2520 and request TB 8-96, ordownload it from http://www.fema.gov/mit/techbul.htm.

Vented enclosures



Table E: Required Uplift Loads

Three Second Gust Wind Speed 90 100 110 120 130 140

Roof/Ceiling AssemblyDesign Dead Load

(psf)

Roof Span(ft.)

Required Uplift Capacity of Connection (lbs.)

12 134 165 199 237 279 323

24 219 271 328 390 458 531

36 306 378 457 544 639 7410

48 393 485 587 698 820 951

12 86 117 151 189 231 275

24 135 187 244 306 374 447

36 186 258 337 424 519 62110

48 237 329 431 542 664 795

12 62 93 127 165 207 251

24 93 145 202 264 332 405

36 126 198 277 364 459 56115

48 159 251 353 464 586 717

12 38 69 103 141 183 227

24 51 103 160 222 290 363

36 66 138 217 304 399 50120

48 81 173 275 386 508 639

12 14 45 79 117 159 203

24 9 61 118 180 248 321

36 6 78 157 244 339 44125

48 3 95 197 308 430 561

Source: 2001 Wood Frame Construction Manual.Values are based on a 12" spacing. To determine connection requirement for different connectorspacing, multiply by the appropriate load multiplier below:

Connection Spacing (in.) 16 19.2 24 48

Load Multiplier 1.33 1.6 2 4

Tabulated uplift loads assume a building located in Exposure B with a mean roof height of 33feet.

48

4



Table F: Stud Selection

3SecondGustSp

eed

(mph)

90

100

110

120

130

NominalStud

Sizes

2x4

2x6

2x

8

2x4

2x6

2x8

2x4

2x

6

2x8

2x4

2x6

2x8

2x4

2x6

2x8

Stud

Length

(ft)

Stud

Spacing

(in)

Minimum

F b

Req

uired(psi)

12

542

220

12

6

669

271

156

810

328

189

964

390

225

1131

458

264

16

723

293

16

8

892

361

208

1080

437

252

1285

520

299

1508

611

351

8

24

1084

439

25

3

1338

542

312

1620

656

377

1927

781

449

2262

916

527

12

819

332

19

1

1011

410

236

1224

496

285

1456

590

339

1709

692

398

16

1092

442

25

5

1348

546

314

1632

661

380

1942

786

453

2279

923

531

10

24

1638

663

38

2

2023

819

471

2448

991

570

2913

1180

679

3418

1384

797

12

1143

463

26

6

1412

572

329

1708

692

398

2033

823

474

2385

966

556

16

1524

617

35

5

1882

762

439

2277

922

531

2710

1097

632

3181

1288

741

12

24

2287

926

53

3

2823

1143

658

3416

138

3

796

4065

1646

947

4771

1932

1112

12

1512

612

35

2

1866

756

435

2258

914

526

2687

1088

626

3154

1277

735

16

2015

816

47

0

2488

1008

580

3011

121

9

702

3583

1451

835

4205

1703

980

14

24

3023

1224

70

5

3732

1511

870

4516

182

9

1052

5374

2176

1253

-

2554

1470

12

1922

778

44

8

2372

961

553

2870

116

2

669

3416

1383

796

4009

1624

934

16

2562

1038

59

7

3163

1281

737

3827

155

0

892

4555

1844

1062

5345

2165

1246

16

24

3843

1556

89

6

4744

1921

1106

5741

232

5

1338

-

2767

1592

-

3247

1869

12

2371

960

55

3

2927

1185

682

3542

143

4

825

4215

1707

982

4947

2003

1153

16

3161

1280

73

7

3903

1581

910

4723

191

2

1101

5620

2276

1310

-

2671

1537

18

24

4742

1920

110

5

5855

2371

1364

-

286

9

1651

-

3414

1965

-

4007

2306

12

2858

1158

66

6

3529

1429

822

4270

172

9

995

5082

2058

1184

5964

2415

1390

16

3811

1543

88

8

4705

1905

1097

5693

230

6

1327

-

2744

1579

-

3220

1853

20

24

5717

2315

133

2

-

2858

1645

-

345

8

1990

-

4116

2369

-

4830

2780

Source:2001WoodFrameConstructionM

anual.Tabulatedbendingstressesassum

eabuildinglocatedinExposureBwitham

eanroofheight

of33feet



Reference Materials for High Wind Construction

American Forest & Paper Association (AF&PA)Wood Frame Construction Manual(2001 High Wind Edition)American Wood Council of AF&PATechnical PublicationsPO Box 5364Madison, WI 53705-5364800-890-7732

www.awc.org

Federal Emergency Management Agency (FEMA)Coastal Construction Manual

[FEMA publications are free; ask for FEMA 55, the Coastal Construction

Manual, and FEMA 20, a catalog of available publications.]

800-480-2520www.fema.gov

Southern Building Code Congress (SBCCI)SSTD 10-99 Standard for Hurricane Resistant ResidentialConstructionSouthern Building Code Congress International, Inc.900 Montclair RoadBirmingham, Alabama 35213-1206 USA205-591-1853www.sbcci.org

Sources of Additional Information

American Society of Civil Engineers1801 Alexander Bell DriveReston, VA 20191-4400800-548-2723www.asce.org

Blue Sky Foundation of NC

920 Main Campus Drive, Suite 100Raleigh, NC 27606919-424-4555 or 919-424-4401 Faxwww.bluesky-foundation.com

FEMA Region IVMitigation Division

3003 Chamblee Tucker Rd.Atlanta, GA 30341770-220-5485



Florida Alliance for Safe Homes (FLASH)1430 Piedmont Drive EastTallahassee, FL 32308877-221-SAFEwww.flash.org

Institute for Business & Home Safety1408 North Westshore Blvd.

Suite 208Tampa, FL 33607866-657-IBHSwww.ibhs.org

North Carolina Sea Grant Extension ProgramCoastal Construction and Erosion Specialist5001 Masonboro Loop Road

Wilmington, NC 28409910-962-2491 or 910-962-2410 fax

www.ncsu.edu/seagrant/

South Carolina Sea Grant Extension ProgramCoastal Hazards Specialist287 Meeting StreetCharleston, SC 29401843-727-6497 or 843-727-0191 fax

www.scseagrant.org

Materials Sources

Sources of Adhesive Weather Stripping Material:

MFM Building Products Corporation800-882-ROOFwww.coshocton.com/mfm/

Protecto Wrap Co800-759-9727

www.protectowrap.com

Bartech International800-341-9917www.ridglass.com



Sources of Automatic Feed Screw Guns:

Quik Drive Corporation888-487-7845www.quikdrive.com

Pam Fastening Technology, Inc800-699-2674

Grabber Construction Products800-477-TURNwww.grabberman.com

Makita USA800-462-5482www.makita.com

Stanley-Bostitch

401-884-2500www.stanleyworks.com

Sources of Power/Pressure Operated Caulk Guns:

Grainger

864-288-0110www.grainger.com

McMaster Carr

404-346-7000www.mcmaster.com

MSC

800-645-7270www.mscdirect.com

Tool Crib of the North800-358-3096www.toolcrib.amazon.com

Caulkmaster800-447-6326

www.caulkmaster.com

Tools-Plus800-222-6133www.tools-plus.com



Finding AFG-01 Rated Adhesives:These adhesives are readily available at home improvement stores.Check for the AFG-01 rating on the tube. These adhesives were largelydeveloped for subfloor applications. You can usually locate them byasking for the subfloor adhesives.

Sources of High-Wind Asphalt Shingles

Tamko Roofing ProductsStormfighter Shingle800-228-2656www.tamko.com

Certainteed CorporationHatteras Shingle610-341-7000

www.certainteed.com

Sources of Metal Connectors/“Hurricane Clips”:

Simpson Strong-Tie800-999-5099www.strongtie.com

USP Lumber Connectors800-227-0470www.uspconnectors.com

Acknowledgements

This guide was prepared by Clemson University graduate studentsMelanie Frank and Alana Walden, under supervision of Dr. Scott Schiff,

Associate Professor of Civil Engineering at Clemson University and Dr.Elizabeth Judge, Coastal Hazards Specialist for the S.C. Sea GrantExtension Program, in cooperation with Mr. Don Markle, Executive

Di t f th Bl Sk F d ti f N th C li I Q ti

protect home from high winds

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