Installing New Roof Over Old

Leave the old valley flashing in place and install new over it.

Installing new roof over old.

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

Looks just as good and lasts as long. Has the same manufacturer s warranty. A properly installed layover roof can look and function as well. But you must take care to install shingles correctly so they lie flat.

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