New Roof Sheathing Over Old

That s also why building codes commonly limit re roofing to no more than two layers.

New roof sheathing over old.

Has the same manufacturer s warranty. The new plywood thickness should be. As long as the new plywood itself can span the distance and carry the roof wind seismic and snow loads for your region adding new ply over old is just fine. Looks just as good and lasts as long.

The existing asphalt shingles need replacement so he plans to do a tear off and re shingle. Installing a new roof over shingles takes less time than tearing off the old roof. But you must take care to install shingles correctly so they lie flat. Construction of a new roof deck for asphalt fiberglass roofing if you re going to add a roof on top of an old one it s a good idea to remove any loose shingles and apply a new layer of 30 pound roofing felt before laying the new shingles.

Going over inadequate thickness plywood for a more solid deck or skip sheathing is fine as long as they pay special note to the ventilation and home the roof is designed to vent. Roy gingrich of ellicott city has a 40 year old house with an asphalt shingle roof surface. As long as it s done right and under the right conditions installing new shingles over old ones can last as long and look just as good as a complete re roof. That must always be accounted for in the roofing design process.

Answered 6 years ago by wowhomesolutions. If conditions are right new shingles laid over old shingles can be just as attractive and durable as shingles laid on bare sheathing. If your roof is in good shape but has some damage to one side from a downed tree or has lost shingles in a wind storm an overlay is worth considering. Installing new roof shingles over old effectively doubles the weight of the roofing so you have to make sure your roof structure can handle the extra load.