level 200 truss installation - dallas area habitat

Level 200 Truss Installation

Mike Proch

1

July 2019

Agenda

Course objectives

Safety & quality

Organization & tools

Truss overview, issues, repair

Truss layout (front wall & porch)

Brace preparation (~ qty / plan)

Alternate Loading of large trusses

2

Agenda (cont’d)Minor truss repair

Setting back gable truss

Issues and solutions

Setting & securing common trusses

Bracing overview

Ladder panel build & install

Sub fascia install

Truss team leadership elements

3

Vision for the end of the day

4

Vision for the end of the day

Requires:▪ Preparation

▪ Team effort

▪ Repeatable processes

▪ Serial/parallel tasks

▪ Appreciation to volunteers

Course Objectives

Expand information from 100 series

Expand FPE implementation

Key area refresher

Install techniques, tips

Common problems and solutions

Assumes familarization with 100 series course

5

Safety & QualitySafety on the ground

Correct lifting and ladder use

Spatial awareness

Safety on the top

Secure everything

Constant communications

Quality is a process

¼ of an inch matters

6

Fall ProtectionMust be used when working over 6’HUGS best solution roof workFPE harnessed trained personnel for truss settingLadders

Do not lean A frame ladders – new ladders purchased are designed to lean

Extension ladders –claws in dirt, pad on concrete

Extend at least 3’ beyond roof

“tie off” at top to prevent slipping

Do not carry shingles on ladders

FPE Usage

8

▪ Inspect equipment

‐ Rips, loose, stitching, cuts

‐ Damaged casing, components

‐ Ensure all function properly

▪ Ensure harness is properly fitted / fastened

9

Tools

Ladders

Tool belt, hammer, 12D and

duplex nails

Tape measures & speed square

Impact driver & screws

8 foot level

Push sticks

Clamps

10

Common truss components

Bottom ChordKing Post

Truss

Webbing

Metal

Gussets

11

Large truss gusset- Top Chord plane

may be impacted

Note:a) Tag does NOT indicate truss install direction

b) Large trusses (e.g. Hawthorne) have non-

symmetrical web bracing over garage/living room

Truss layout

Check wall bracing & alignment/plumb

Double check level for accuracy

Review truss plan (included with trusses)

Use 100 foot tape for measurement

Working back to front (house sides and center caps))1 (first common) to #? (last common before gable), label gable (GG)

Working front to back (porch)Continue sequential label numbering

Marks visible & consistent

Snapping a 1” line on the longer wall

12

Label on cap plate inside dimension on non 24” O.C. trusses

Gable nailer for back gable truss

R01

Back

Gable

R02

Large

Common

Truss

R03

Garage

Gable

R04

Small

Common

Truss

R05

Porch

Gable

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Pull line to ensure layout is

consistent from living room

across the garage wall

Truss layout issuesCrown in slab impacting truss install

String across outside walls to determine

impact (also see back gable issues tip)

Tip: Mark truss layout to hall walls in case

cap plate “dado” is required.Common truss lays on Front wall and “rocks”

Move to front of wallEnsure front wall is secured (Hint: use 2x6 scraps

as deadwood and truss nailer – secures wall)

14

Brace preparationUse house plans to determine brace needs prior to build day

Reuse bracing from other builds if possible

Build while truss staging and/or earlier (day 1)

Typical “Magnolia Plan” needs:

15

Plan Strong

-backs

Ext.

Lats.

Int.

Web

Rat

Runs

K-

Brace

*T-

Blocks

Push

Sticks

12’ Ext Brace(1)

Magnolia 2 10 10 10 5 14 Min. 6 10

Based on 16’ 2x4s(1) External diagonal bracing

Internal diagonal bracing may vary in size but typically runs 7-8’ (see later slides)

* Make T-Top at least 6”

Staging trusses

Identify truss staging destinations

Use enough volunteers

Review lifting mechanics & flow

Sort trusses by type

Make 1” mark (1) (bottom chord) and 9’ (topchord). 9’ for external lateral brace placementMove trusses to staging locations

Inspect trusses before / during movement for issues

Repairing truss (see chart) before loading is easier

than repairing once erected

16

Note (1): (Bottom chord – house width)/2 + 1” measured from top chord end

Staging trusses

17

Suggested Loading Pattern

18

Porch

Garage

Gable

Back

Gable

Note: Ensure porch beams installed before loading trusses!

Gable + 6

commons

Gable +

~17

commons

Spacing permits

push stick lift

effort

Load after main

trusses erected

Check gable

labels to ensure

which is front

and back!

Alternative Loading Process for Large Trusses

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Step 1: Prepare the bracing to holdthe trusses.

Step 2: Lay the truss on the bracing rails with thebottom cord resting in the "V" of the stakes

Alternative Loading Process for Large Trusses

20

Step 3: Using push sticks, push the trusses up thebracing

Step 4: As the top of the truss reaches the top of the wall, guide the truss along the wall for thevolunteers

Truss repair

During truss delivery, staging and/or loading, truss elements may be cracked or truss gussets have separated

Contact Construction Supervisor

Repair magnitudeMinor: crack/break permitting at least 8’ scabs centered on the crack

Major: Minor criteria not possible or gusset separation (mfgr. direction)

21

Truss Repair (cont’d)Minor web / chord repair

Install 2x4s on the front and back of the element that extends at least 4’ on either side of the crack/break.

Add construction adhesive and nail with 12 D nails alternating from front and back scabs at 6” max. intervals. Similar to wall nailing pattern.

22

Construction adhesive (both sides if available)

6”

6”

Setting back gable truss

Installation of strongbacks

Raising of gable into position

Placement with gable nailer

Overhang alignment

Bottom chord nailing pattern

Attach to strongbacks

23

Strongback and Gable Installation

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Secure to wall studs with screws

Raise back gable

Use screws to attach gable to strongbacks

Leave strongbacksinstalled until back K / Internal bracing is complete and ladder panel install start

Back gable install issues

Slab crown results in rocking trussCheck before loading trusses (string across outer corners)Tip: Check for back wall crown before installing the backwall cap plates (ref. truss layout crown)

SolutionsGaps 3/8” or less use shimsLarger gaps require trim of cap plates

Pop line from outside corner to outside corner to identify area to remove

25

Setting Common Trusses

Assemble 3 teams

Raising, wall attachment, top chord bracing

Temporary bracing inventory

Following the quarterback

Aligning in two dimensions

Bottom chord center set to 24” intervals

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Setting common trusses

27

Secure

temporary

bracing

with

Duplex

nails

Securing Common Trusses to Wall

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Figure 5-12

Install:▪ 3 nails (2 one side, 1

opposite) – 12D

▪ Gusset placement may

require nailing through the

gusset

Nail ~1” up to prevent

chord

splitting

Truss Bracing Overview

Purpose

Temporary (external) and Permanent (internal) bracing to support truss

location and provide stability against unintended forces / movement

(e.g. gravity, wind, seismic, etc.) and secure for FPE

Internal K braces to provide lateral force support to gables

Lateral and Diagonal bracing shown below:

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Figure 5-14

May be needed for 38’+ trusses

A A

AB

C C

D D

E

E

E

E

F

F F

F

BA

Temporary Laterals

Permanent Laterals

Rat Runs

Subfascia

Temporary Diagonals

Permanent Diagonals

A

B

C

D

E

F

External Truss Bracing (FPE)

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Strongbacks

Laterals

Diagonals

10 truss spaces

/ 20’ max

~45o

2 bay overlap

FPE used

after first 5

trusses

installed

Common truss temporary braces

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Use DUPLEX nails for easy removal

External Braced Trusses

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FPE Usage Tips

Where possible, have two harnessed

volunteers per side to install bracing and

help move Safety Bar (“red bar”)Use two “safety bars” per side in hop scotchmanner to facilitate easier movement and

truss alignment (if qualified people & bars

available)

Keep “safety bars” above ext. lateral whenpossible

33

Internal Permanent Bracing

Rat Runs / “Cal” corner

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Laterals

2 bay overlap

“K” braces Lateral braces Diagonal braces

Rat Runs

2 bay overlap

Internal diagonals

installed every 10 truss

spaces (20’ max)

Lateral and

Diagonal

bracing on both

center webs

Use duplex nails top lateral

35

Back of house

Permanent Internal Bracing

Interior PermanentBracing

Purpose

Ensure trusses and roof structure won’t rack when subjected to strong winds

2 types: Diagonal (K and web) and lateral

Installation

K Diagonal (perform first)Large gable trusses have 3 K braces (center, 4-6’ left and right of center)Attached typically to California corner or King Post (depends on house plan) K Brace (Magnolia)

36

Figure 5-17

Figure 5-18

Interior Permanent Bracing

Installation (cont’d)Lateral Bracing

Attached to truss interweb ~ 4’ from bottom bottom chord. Start on first common truss

Diagonal BracingTwo 8’ 2x4s (top / bottom) start on first common angled to lateral brace from the back. Repeat every 10 truss spaces. Front diagonals start on last common toward lateral (NOTE: use duplex nails on first common top diagonal to ease ladder panel install

CheckK brace down 2” from peak to clear ladder panelBraces adequately nailed (12d, fully seated)

37

Hurricane TiesPurpose:

A connecting tie to provide structural load path to resist high winds

Installation1 tie/truss installed to wall or porch beam with Simpson nails only

NEW: add tie to every other truss on longest hall wall

Where truss is too close to interior wall, do not install

Check:Vertical position (wall board issue), 10 nails and fully seated (not proud)

Ensure truss is straight up and not slanted before installing

TipNeedle Nose pliers and/or a palm nailer makes install for volunteers easy

38

Ladder Panels (aka Lookout Ladders)

Purpose

Provides strong overhang structure for the

eave of the gables

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Figure 5-23

Ladder Panel construction

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Lookout rung length derivation

5.7.1 BUILDING LADDER PANELS

Ladder Panel construction (cont’d)

Roof Pitch Tail Peak Tie-In Tail*

4 18½° 18½° 53°

5 22½° 22½° 45°

6 26½° 26½° 37°

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Figure 5-26. Ladder Panel Rung Placement

Table 5.1 Angles for Cuts

Ladder Panel Construction (>16’)

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Extension ConstructionTips:• Ensure flyrafters have minimal

warpage

• Screw rungs (in addition to

normal nailing) to flyrafters to

minimize separation on install

Figure 5-27. Ladder Panel Longer than 16 Feet

Figure 5-28. Ladder Panel Extension

Install extension

after the large

ladder is installed

and secured.

Ladder Panel Bullen Board

43

Tips:• Ensure Bullen board material is

straight as possible

• Mark each rung separately for

board placement – DO NOT use

a chalk line

• Pull diagonal measurements to

ensure squareness before

nailing Bullen boardMeasurements based on

trusses spaced 24” O.C.

Bullen Board purpose – secure ladder to

gable and assist in ladder straightness,

particularly with warped gable or first

common trusses

Figure 5-30. Bullen (Stop) Board

Ladder Panel Install Sequence

Align inside flyrafterpeak to 1st common peak, nail common side and ladder side

After outside flyrafterpeaks are aligned and nailed, nail gable to “bullen” boardLarge ladders, add extension (slide down to align with house rafter tails)

44

Figure 5-31. Installation of Ladder Panels

Ladder Panel Install Issues/Fixes

Panel is not level “Pagoda Effect”

Typically caused by gable out of plane with roof (slab, positioning, etc.)

If gable position is corrected or OK

Minor adjustment of inside flyrafterposition height may allow reasonable alignment to roof plane

For more severe case, make a small notch to the ladder rungs where they sit on the gable

Use 8’ level to determine notch height (align to plane of roof)

DO NOT MODIFY the truss

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Not Level

Common Gable

Ladder Panel Install Issues/Fixes

Ladder peaks out of alignment horizontally

Typically driven by gaps in rung to flyrafters or twisted flyrafters

If rungs are nailed tightly, consider driving 1-2 2” roofing nails to achieve plane for fascia install or add shim

46

¼” or less

Ladder Panel Blocking

47

Before blocking, ensure rung toe nailed to gable

Add 2x4 blocking between ladder rungs

Note: Blocking is on top of the gable (not side of)

Figure 5-30. Ladder Panel Blocking

Placement

Subfascia

PurposePermanent truss tail bracing enabling fascia and soffit installation and support to the roof deck

Installation2”x4” - 16’ nailed (2) to truss tail positioned with speed square (see photo)Must be straight down eave, shim/cut tails as required (process follows)

Note: truss bottom chord “nib” may drive averaging subfascia install from tail to tail

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Figure 5-21

Subfascia Install Prep

It is critical that the subfascia is as straight as possible going down the length of the

house

Aesthetics, decking and minimize soffit gaps

Recommend a quick string line check to ensure straightness.

Issues corrected with shims or trimming

Suggested procedure follows

49

Stringing Rafter Tails

50

1st

ba

ck c

om

mo

n

Cap Plate

StringMark or

measure gap

when square

touches line

Bent 12D

nail, string

attached

Process:• Drive 12D nail into end of rafter tail and

bend up, hammer flush with tail end

• Slide square to mark cut or measure

gap

• Use 8’ level for remaining truss tails

1st

fro

nt

com

mo

n

Front/Back common

Shim gap

Truss team leadership elements

Trusses are a team effort

Drafting your teams

Finding your quarterbacks

Clearly explain tasks and context

Repeatable processes

Serial & parallel tasks

Say thanks

51

Questions?

52

Mike Prochmlproch@att.net

214-415-0063

Thanks!

53

54

Slope tailed common truss

55

Bottom Chord “Nib” varies 0” – ½”

Nib Issue:

- May affect roof plane

- Impacts sub fascia install

Eliminate slide?

56

Marking temporary/permanent lateral bracing

Marking flat truss overhang

57

Figure 5-7

Loading trusses

58

Figure 5-11

Rat Run Layout

59

Figure 5-19

Smaller trusses (~30’) = 2 Rat Runs @ 1/3 spacing (e.g. Trinity & Magnolia)Larger Trusses (~38’) = 3 Rat Runs @ ¼ spacing (e.g. Hawthorne & Hickory)

Add 3rd Rat Run

for large truss

~10’ spacing

Stringing Rafter Tails

60

1st

ba

ck c

om

mo

n

Cap Plate

String

Mark or measure

gap when jig touches

line

Bent 12D

nail, string

attached

Process:• Drive 12D nail in and up, hammer flush

with tail end

• Make jig, 2x4 cut 22.5o attached to

scrap 2x4

• Slide jig to mark cut or measure gap

• Use 8’ level for remaining truss tails

1st

fro

nt

com

mo

n

Front/Back

common

Shim or

scab gap