Installing New Roof Over Old

But you must take care to install shingles correctly so they lie flat.

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. 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. Installation is easier than for a tear off job because you can use the existing shingles as guides for laying the new ones. Installing a new roof over shingles takes less time than tearing off the old roof.

To level out an existing asphalt shingle roof rip down reduce the height of two courses of shingles as shown in the drawing below. A properly installed layover roof can look and function as well. That s also why building codes commonly limit re roofing to no more than two layers. 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.

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. Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option.