REPAIR AND/OR REPLACEMENT OF VARIOUS

ROOFING MATERIALS

ARCCA IncorporatedPrepared by

Randal L. Exley P.E., S.E.

Capstone Structural

Engineering & Consulting, P.C.Structural consultants for ARCCA Incorporated

PAMIC Claims Summit 2013

General Considerations: In general, most roof covering materials are not structural in nature and

can be repaired, or removed and replaced without affecting the integrity of the underlying structure.

Plywood, oriented strand board (OSB) or wood plank roof sheathing are considered as a part of the roof’s structural system as the sheathing carries vertical load (i.e. the dead load of the roofing system and superimposed loads due to foot traffic, snow, wind, etc.) and acts as a shear diaphragm for lateral forces (wind or seismic) and also provides lateral support for the roof framing to prevent lateral torsional buckling (i.e. the joists rolling out of their vertical orientation.) These elements, if damaged, can generally be repaired by removing the damaged portions and replacing them in-kind. Particular care should be taken to assure that the roof sheathing is properly fastened to the structural elements, both to secure it into place and to provide lateral support for the roof framing.

General Considerations continued: Structural metal roof decking is commonly installed under built-up or

rubber membrane roofing systems with rigid insulation between the roofing and the decking. The metal roof decking is also considered as a part of the roof’s structural system as the decking carries vertical load (as previously described) and acts as a shear diaphragm for lateral forces and provides lateral support for the roof framing. Replacement of metal decking can be somewhat more complicated, as the span rating of metal roof decking is often based on a continuous multiple-span condition. The roof decking may not be sufficient for a single span condition. When determining how much of the decking must be removed and replaced, this should be taken into consideration. Again, particular care should be taken to assure that the roof decking is properly fastened to the structural elements, both to secure it into place and to provide lateral support for the roof framing. This is particularly critical when the roof framing system consists of tall slender elements such as open web steel bar joists or cold formed light gage metal purlins which rely on the roof decking for support against lateral torsional buckling. Connections between metal roof decking and steel framing typically consist of puddle welds or self tapping sheet metal screws at a spacing not exceeding 12 inches.

Building Code Considerations:

International Existing Building Code 2009 (Current in Pennsylvania):

The International Existing Building Code (IEBC 2009) CHAPTER 5 REPAIRS, SECTION 502 BUILDING ELEMENTS AND MATERIALS, Subsection 502.2 New or replacement materials, states: “Except as otherwise required or permitted by this code, materials permitted by the applicable code for new construction shall be used. Like materials shall be permitted for repairs and alterations, provided no dangerous or unsafe condition, as defined in Chapter 2, is created.”

As such, there should be no issues with an “in-kind” replacement of damaged roofing materials, from strictly a material standpoint.

Building Code Considerations continued: What is a “dangerous or unsafe condition” as defined by the IEBC?

Chapter 2 of the IEBC defines “dangerous” as follows: “Any building, structure or portion thereof that meets any of the conditions described below shall be deemed dangerous:

1. The building or structure has collapsed, partially collapsed, moved off its foundation or lacks the support of the ground necessary to support it.

2. There exists a significant risk of collapse, detachment or dislodgement of any portion, member, appurtenance or ornamentation of the building under service loads.”

Building Code Considerations continued: Chapter 2 of the IEBC defines “unsafe” as follows: “Buildings, structures or

equipment that are unsafe or that are deficient due to inadequate means of egress facilities, inadequate light or ventilation, or that constitute a fire hazard, or in which the structure or individual structural members meet the definition of “Dangerous,” or that are otherwise dangerous to human life of the public welfare, or that involve illegal or improper occupancy or inadequate maintenance shall be deemed unsafe.”

Most or all of the above conditions warrant a “common sense” approach to loss adjustment. It is noteworthy that risk of detachment or dislodgement of any appurtenance or ornamentation of the building constitutes a dangerous condition. I would interpret this to include flashings, trim, gutters, etc.

Building Code Considerations continued: The International Existing Building Code (IEBC 2009) CHAPTER 5

REPAIRS, SECTION 502 BUILDING ELEMENTS AND MATERIALS, Subsection 502.1 Existing building materials, states: “Materials already in use in a building in conformance with requirements or approvals in effect at the time of their erection or installation shall be permitted to remain in use unless determined by the code official to render the building or structure unsafe or dangerous as defined in Chapter 2.” Note that it is the code official’s responsibility to make the determination as to whether materials already in use render the building or structure unsafe or dangerous, and to order corrections made as he/she deems necessary. (Emphasis added mine.)

Building Code Considerations continued: As for whether the materials were installed in conformance with

requirements or approvals in effect at the time of their erection or installation is a more difficult determination. Since Pennsylvania did not adopt a statewide building code until 2004 and more rural municipalities often had no adopted codes prior to 2004, where does that leave us? We can compare field conditions with the nationally recognized model building codes (BOCA, CABO) that existed at the time of the erection or installation of the materials. But what about approvals? It has been my experience in performing forensic investigations of insurance losses that the level of building code enforcement has varied widely, in some cases being non-existent. I would again suggest reverting to the nationally recognized model building codes that existed at the time of the erection or installation of the materials as a basis for evaluation.

Building Code Considerations continued: International Building Code 2009 (for industrial, commercial or multi-family

residential structures) or the International Residential Code 2009 (for one and two family dwellings):

Code requirements for roof coverings in the 2009 IBC are found in Section 1507 Requirements for Roof Coverings and in the 2009 IRC are found in Section R905 Requirements for Roof Coverings.

It has been my experience that most of the problems associated with an “in-kind” repair or replacement of roof coverings revolves around existing roof coverings being installed outside of the parameters for which they were intended to be installed (i.e. being installed on a slope that is less than what is approved for the materials used or being installed over improper substrates (underlayment and/or sheathing.))

Asphalt Shingles:

Both the IBC & IRC codes have similar requirements for asphalt shingles, which are as follows:

Asphalt shingles shall be used only on roof slopes of 2 units vertical in 12 units horizontal or greater. It is not uncommon to see this standard violated.

For roof slopes from 2 units vertical in 12 units horizontal up to 4 units vertical in 12 units horizontal, asphalt shingles can be used, but they must be installed over double underlayment. It is not uncommon to see this standard violated.

Asphalt Shingles continued:

Asphalt shingles shall be fastened to solidly sheathed decks. Of note, older roofs which once were covered with slate tiles or terra cotta barrel tiles may have been constructed with intermittently sheathed roofs (i.e. wood strips or wood plank sheathing with wide gaps between the sheathing boards.) These types of sheathing systems are not suitable for the installation of asphalt shingles, and must be removed and replaced or overlaid with continuous plywood or OSB sheathing. It should be noted that this modification may affect the ventilation characteristics of the attic space or enclosed rafter cavities and this should be evaluated.

Underlayment must conform to ASTM D 226 Type I, ASTM D 4869 Type I or ASTM D 6757.

Ice barriers must be installed along the eaves to a point not less than 24 inches inside of the exterior wall line of the building.

Open valleys must be lined with 24 inch wide non-corrosive metal or 2 plies of rolled mineral roofing with the bottom layer being 18 inches wide and the top layer being 36 inches wide.

Asphalt Shingles continued:

Closed valleys must be lined with one ply of smooth rolled roofing at least 36 inches wide or the valley linings approved for open valleys. Self-adhering modified bitumen underlayment complying with ASTM D 1970 can be used in lieu of the lining material.

Flashings against vertical side walls or chimneys must be installed using the step flashing method.

Slate and slate type shingles: Slate shingles shall be fastened to solidly sheathed decks. As noted above,

intermittently sheathed roofs (i.e. wood strips or wood plank sheathing with wide gaps between the sheathing boards) are no longer permitted for slate tile shingles and must be removed and replaced or overlaid with continuous plywood or OSB sheathing. Also as stated above, this modification may affect the ventilation characteristics of the attic space or enclosed rafter cavities and this should be evaluated.

No longer approved Approved

Slate and slate type shingles:

Slate shingles shall be used only on roof slopes of 4 units vertical in 12 units horizontal or greater.

Underlayment must conform to ASTM D 226 Type I, ASTM D 4869 Type I or II.

Ice barriers must be installed along the eaves to a point not less than 24 inches inside of the exterior wall line of the building.

Wood shingles:

Wood shingles shall be installed on solid or spaced sheathing. In areas where the average daily temperature in January is 25 degrees F or less, solid sheathing is required on that portion of the roof requiring the application of an ice barrier.

Wood shingles continued:

Underlayment must conform to ASTM D 226 Type I, ASTM D 4869 Type I or II.

Ice barriers must be installed along the eaves to a point not less than 24 inches inside of the exterior wall line of the building.

Wood shingles continued: Wood shingles shall be used only on roof slopes of 3 units

vertical in 12 units horizontal or greater.

Questionable slope?

Low Slope Roofs:

Mineral-surfaced roll roofing:

Mineral-surfaced roll roofing shall be fastened to solidly sheathed decks.

Underlayment must conform to ASTM D 226 Type I, ASTM D 4869 Type I or II.

Mineral-surfaced roll roofing shall not be applied on roof slopes below one unit vertical in 12 units horizontal.

Ice barriers must be installed along the eaves to a point not less than 24 inches inside of the exterior wall line of the building.

Low Slope Roofs continued:

Thermoset single-ply (EPDM rubber roofing):

Thermoset single-ply membrane roofs shall have a design slope of a minimum of one-fourth unit vertical in 12 units horizontal (2-percent slope) for drainage.)

Low Slope Roofs continued:

Built-up roofs:

Built-up roofs shall have a design slope of a minimum ¼ units vertical in 12 units horizontal for drainage, except for coal tar built-up roofs which shall have a design slope of a minimum of 1/8 units vertical in 12 units horizontal.

Low Slope Roofs continued:

Metal roofs:

Metal roof panel roof coverings shall be applied to solid or spaced sheathing, except where the roof covering is specifically designed to be applied to spaced supports.

The minimum slope for lapped, non-soldered-seam metal roofs without applied lap sealant shall be 3 units vertical in 12 units horizontal.

Low Slope Roofs continued:

Metal roofs continued:

The minimum slope for lapped, non-soldered-seam metal roofs with applied lap sealant shall be ½ units vertical in 12 units horizontal.

Low Slope Roofs continued:

Metal roofs continued:

The minimum slope for standing seam roof systems shall be ¼ units vertical in 12 units horizontal. In general, standing seam metal roofs are not structural in nature. Removal and replacement of only damaged portions of standing seam metal roofs can be potentially difficult depending upon how the standing seams are interlocked.

Low Slope Roofs continued:

Ventilation issues:

It should be noted that inadequate ventilation of attics or enclosed rafter cavities can lead to many problems including:

• A build-up of condensation, which can result in fungal growth and/or premature deterioration of the roof sheathing material.

• Heat build-up and premature deterioration of the roof covering materials.

• Ice damming.

Improper or inadequate ventilation of attics or enclosed rafter cavities should always be corrected.

REPAIR AND REPLACEMENT OF VARIOUS FLOOR

COVERING MATERIALS

Capstone Structural

Engineering & Consulting, P.C.

General Considerations:

In general, most floor covering materials are not structural in nature and can be repaired, or removed and replaced without affecting the integrity of the underlying structure. Some unusual situations may require additional consideration:

Wood plank flooring:

In some older homes it is not uncommon for wood plank flooring to be installed directly over the wood floor joists. Similar to my previous comments regarding wood plank roof sheathing, wood plank flooring installed directly over the wood floor joists should be considered as a part of the floor’s structural system as the flooring carries vertical load (i.e. the dead load of the flooring and the code required superimposed live load), acts as a shear diaphragm for lateral forces (wind, seismic and lateral earth pressure) and also provides support against lateral torsional buckling for the floor framing. These elements, if damaged, can generally be repaired by removing the damaged portions and replacing them in-kind. Particular care should be taken to assure that the flooring or floor sheathing is properly fastened to the structural elements, both to secure it into place and to provide lateral support for the floor framing.

Ceramic or porcelain tile flooring continued:Over wood framing systems:

Most floor framing systems are designed to limit live load deflections to 1/360th of the joist span length. Publications from the Tile Council of North America (TCNA) indicate that“Recent research has shown tile to fail, under some conditions, when the floor is more rigid than L/360. In fact, failures at L/600 have been observed. It is for this reason that recommendations for floor rigidity

are not based on deflection

measurements but on empirically

established methods found to work

over normal code construction.”

Ceramic or porcelain tile flooring continued:Over wood framing systems continued:

Publications from the Tile Council of North America (TCNA) also indicate that “The most current ANSI standards for tile installation (A108 - 1999) specifically exclude OSB. This is not to say that tile cannot be installed reliably over an OSB subfloor; however, there is significant debate in the tile industry regarding the conditions necessary for a long-lasting successful installation. The allowable ambient moisture level, extent of moisture related swelling before tiling, blocking and bracing and many other issues are still being debated. Each installation materials manufacturer has their own criteria and proprietary methods and requirements. Some backerboard companies will warrant installations using their products over OSB; however, their specific methods must be followed. Note: thinset manufacturers do not recommend installing ceramic tile directly to OSB. Refer to the TCNA Handbook for recommended systems that include OSB, and follow manufacturer's literature for instructions and cautions.”

Ceramic or porcelain tile flooring continued:Over concrete slabs on grade continued:

The most common problems I encounter with ceramic or porcelain tiles installed over concrete slabs on grade occur as follows:

Moisture vapor transmission through the slab causes the tile adhesives to deteriorate. This is common in older homes where there was no vapor barrier installed under basement slabs on grade.

Movement of the concrete slab due to thermal expansion and contraction and missing or inadequate tile expansion joint to accommodate this movement, causing stresses in the tiles and/or the adhesives at the tile/slab interface. This eventually results in cracking or “tenting” of the tiles.

Ceramic or porcelain tile flooring continued:Over concrete slabs on grade continued:

Obviously an “in-kind” replacement would not be appropriate in either of these two situations.

Vapor transmission problems are difficult to deal with. Options include floor coatings that limit vapor transmission or the use of alternate flooring materials.

Movement of the concrete slab is easier to deal with, and typically only requires the addition of expansion joints in the tiling, coinciding with the locations of the slab joints.

ANSI Specifications for the Installation of Ceramic Tile ANSI A108.5 contains recommendations for the installation of ceramic tile, including the following:

Ceramic or porcelain tile flooring continued:Over concrete slabs on grade continued:

Section AN-2.6.1.1 states “Crackfree concrete floors not subject to bending and deflection or crackfree concrete fill over such floors may have mortar and tile bonded to them, Specify such floor surfaces to have a screed finish.”

Section A-3.1.2 states that “If tile is to be bonded directly to concrete floor with one of the thin-set methods the slab shall have a steel trowel and light broom finish.”

Section A-3.4.1 states “Extend openings for expansion joints completely through the tile setting material, mortar bed and reinforcing down to but not through, waterproofing or cleavage membrane.” And “Expansion joints mat not be needed in very small rooms (less than 12 feet [3.7 m] wide) and also along the sides of narrow corridors (less than 12 feet [3.7 m] wide.)”

Ceramic or porcelain tile flooring continued:Over concrete slabs on grade continued:

Section A-4.3.3.2.2 states that “Tile shall not be applied to skinned over mortar.”

Section A-4.3.3.3.1 states “Press tile into freshly combed mortar, insuring mortar contact with tile while maintaining accurate joint alignment and spacing.”

Section A-4.3.3.3.2 states “Thoroughly beat all tile or tile assemblies into place with a beating block to obtain maximum contact of thin-set mortar on the back of each tile, or back of each tile and back mounting material. Average contact area shall not be less than 80 percent except on exterior or shower installations where contact area shall be no less than 95 percent when no less than three tiles or tile assemblies are removed for inspection.”

Ceramic or porcelain tile flooring continued:Over concrete slabs on grade continued:

Section A-4.3.3.3.4 states “Obtain 100 percent contact with rib-backed tile by trowelling a layer of mortar on the back of each tile prior to placing in the combed mortar bed.”

In addition, in the Tile Council of America, Inc. 1985 Handbook for Ceramic Tile Installation, Page 12 indicates, for a Dry-Set Mortar or Latex-Portland Cement Mortar F113-85, expansion joints are mandatory in accordance with Method EJ711. Installation specifications per ANSI A108.5. Page 28 Vertical and Horizontal Expansion Joints states. Notes: “In very small rooms (less than 12’ wide) and also along the sides of narrow corridors (less than 12’) expansion joints are not needed.” This does not specifically state, but clearly implies that expansion joints are required in rooms over 12 feet wide.

Capstone Structural

Engineering & Consulting, P.C.11676 Perry Hwy., Suite 3209

Wexford, PA 15090

Phone: 724-933-4622 Fax: 724-933-4625

ARCCA Incorporated1000 ALLEGHENY BUILDING

429 FORBES AVENUE

PITTSBURGH, PA 15219

PHONE 866-502-7222 FAX 412-566-6798