I hired a local roofer to redo my roof. One of the items in the contract is to "INSTALL 7/16” OSB SHEATHING OVER EXISTING ROOF BOARDS." The roof boards are rough sawn 3/4 inch thick pine, with a 1/2 - 3/4 inch gap between them. Yesterday I found out they installed the roof without sheathing. The roofer claims that they decided it wasn't necessary. He says installing architectural shingles over wood planks is a widespread practice, and has offered me a 10% discount. Apart from the fact that I think he shouldn't have made this decision without consulting me, I'm trying to find out to what extent the lack of sheathing will compromise the quality or lifespan of the roof. If there's a problem, the discount won't take me far. Would appreciate any advice or suggestions!
One of the first things you might want to do is look into the building codes in your area to make sure that the work performed meets code. In Montgomery County, Ohio planked sheathing is considered spaced sheathing. Therefore as roofing contractors, due to code, we have to install 3/8 or 7/16 OSB over-top of the existing planks to meet building code. Many contractors in my area do not know this code, or if they do they just ignore and continue to violate. Hope this helps and best of luck with your situation.
- Can I use the existing roof sheathing? Section 905.2.1 states “Asphalt shingles shall be fastened to solidly sheathed decks.” Therefore, if the existing sheathing is in structurally sound, it can be used for the new installation. Exception: If the existing roof sheathing is spaced lumber or damaged such that it will not hold a nail, it must be covered or replaced.