New Roof Sheathing Over Old

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.

New roof sheathing over old.

The existing asphalt shingles need replacement so he plans to do a tear off and re shingle. Installation is easier than for a tear off job because you can use the existing shingles as guides for laying the new ones. If conditions are right new shingles laid over old shingles can be just as attractive and durable as shingles laid on bare sheathing. Looks just as good and lasts as long.

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. Find a pre screened local roofing contractor. 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. 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 a new roof over shingles takes less time than tearing off the old roof. Has the same manufacturer s warranty. Roy gingrich of ellicott city has a 40 year old house with an asphalt shingle roof surface. 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.

That s also why building codes commonly limit re roofing to no more than two layers. That must always be accounted for in the roofing design process. Answered 6 years ago by wowhomesolutions. 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.