Installing New Roof Over Old

Along the rakes install a new j channel drip edge which wraps around the old rake flashing and starter courses.

Installing new roof over old.

Looks just as good and lasts as long. Has the same manufacturer s warranty. Installing a new roof over shingles takes less time than tearing off the old roof. Leave the old valley flashing in place and install new over it.

Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option. 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 s also why building codes commonly limit re roofing to no more than two layers. To level out an existing asphalt shingle roof rip down reduce the height of two courses of shingles as shown in the drawing below.

But you must take care to install shingles correctly so they lie flat. If conditions are right new shingles laid over old shingles can be just as attractive and durable as shingles laid on bare sheathing. A properly installed layover roof can look and function as well.