New Roof Sheathing Over Old

If conditions are right new shingles laid over old shingles can be just as attractive and durable as shingles laid on bare sheathing.

New roof sheathing over old.

Nailing new shingles over existing ones is less expensive and faster requiring less labor but it also means you lose the chance to assess the sheathing for signs of water damage. 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 must always be accounted for in the roofing design process. 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.

Answered 6 years ago by wowhomesolutions. Find a pre screened local roofing contractor. But you must take care to install shingles correctly so they lie flat. Has the same manufacturer s warranty.

Installation is easier than for a tear off job because you can use the existing shingles as guides for laying the new ones. 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. The new plywood thickness should be.

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