Roof Decking, H Clips for 2008

[pbennett1]

The new construction home (2008) I inspected today has a roofing issue.
The OSB particle board is stamped 7/16" and the builder states that they used 3/4" due to the upgraded 30 year GAF timberline roof. The buyer has proof in writing what the builder stated.

Besides this mis-representation by the builder, what does the 2006 IRC require?
Plus the H-clips are stamped 1/2". Is this a problem?
Thanks,
Peter

[Jerry Peck - Codeman]

Hi Peter,

From the 2006 IRC. (underlining and bold are mine)
- R803.2.2 Allowable spans. The maximum allowable spans for wood structural panel roof sheathing shall not exceed the values set forth in Table R503.2.1.1(1), or APA E30.

- TABLE R503.2.1.1(1)
- - ALLOWABLE SPANS AND LOADS FOR WOOD STRUCTURAL PANELS FOR ROOF AND SUBFLOOR SHEATHING AND COMBINATION SUBFLOOR UNDERLAYMENT a, b, c
- - - Span Rating column - 24/16
- - - Nom. Thickness col. - 7/16"
- - - Max. Span w/ edge support - 24"
- - - Max. Span w/o edge support d - 24"
- - - Total Load column - 50 psf
- - - Live Load column - 40 psf
- - - Max. Span for Subfloor col. - 0"
- - Notes:
- - - a. The allowable total loads were determined using a dead load of 10 psf. If the dead load exceeds 10 psf, then the live load shall be reduced accordingly.
- - - b. Panels continuous over two or more spans with long dimension perpendicular to supports. Spans shall be limited to values shown because of possible effect of concentrated
loads.
- - - c. Applies to panels 24 inches or wider.
- - - d. Lumber blocking, panel edge clips (one midway between each support, except two equally spaced between supports when span is 48 inches), tongue-and-groove
panel edges, or other approved type of edge support.

Okay, not knowing what the design loading is, but presuming the design loading is within the limits allowable for 7/16" structural panels, 7/16" will span 24" with or without clips. Using oversize clips is almost like not using clips, but worse (not structurally but because the clips can tip and tear through the dry-in underlayment for the roof covering, which could contribute to, and lead to, roof leaks).

Here are some thoughts:
- 1) The builder owes the buyer a significant amount of money. Not just "the difference between" having used 3/4" as the builder stated and having used 7/16" as you found, but for "the cost or removing the roof, removing the roof sheathing, installing the proper 3/4" roof sheathing, and re-roofing", including any and all incidental costs resulting from that work, such as due to wind, rain, snow, loss of living quarters, etc.

The above also takes care of the improper use of the wrong size clips.

At first thought, reading the above may indicate that the 2006 IRC would approve of the 7/16" roof sheathing, however, the IRC also requires:
- R106.1 Submittal documents. Construction documents, special inspection and structural observation programs and other data shall be submitted in one or more sets with each application for a permit. The construction documents shall be prepared by a registered design professional where required by the statutes of the jurisdiction in which the project is to be constructed. Where special conditions exist, the building official is authorized to require additional construction documents to be prepared by a registered design professional.
- R106.4 Amended construction documents. Work shall be installed in accordance with the approved construction documents, and any changes made during construction that are not in compliance with the approved construction documents shall be resubmitted for approval as an amended set of construction documents.

The structure must be constructed in accordance with the approved construction documents. Do you know what was shown on the plans or submitted as "amended construction documents"?

If only 7/16" is shown, then the builder delivered a defective structure as it was not in accordance with the contract and agreement with the buyer.

If 3/4" is shown on the approved plans or approved submitted changes, then the builder ALSO delivered a defective structure *not in accordance with the code*.