But you must take care to install shingles correctly so they lie flat.
Installing new roof over old.
Manufacturers will still warranty the roof for the same amount of time as a re roof as long as it s done by a qualified installer.
That s also why building codes commonly limit re roofing to no more than two layers.
If conditions are right new shingles laid over old shingles can be just as attractive and durable as shingles laid on bare sheathing.
Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option.
Along the rakes install a new j channel drip edge which wraps around the old rake flashing and starter courses.
Leave the old valley flashing in place and install new over it.
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.
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.
Installing a new roof over shingles takes less time than tearing off the old roof.
A properly installed layover roof can look and function as well.
Has the same manufacturer s warranty.