Installing A New Roof Over An Existing One

A properly installed layover roof can look and function as well.

Installing a new roof over an existing one.

Some roofers install a layer of waterproof shingle underlayment wsu over the existing shingles at the eave end as would be done for a roof laid on bare sheathing. 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. This saves labor costs as all ladders and other equipment are already in place.

It is not possible to mix materials nor to install a new layer over slate or wood tiles. Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option. Has the same manufacturer s warranty. Installing a new roof over an existing one can only be done if you have shingles because you can only put shingles over shingles.

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. This provides a safer environment for both workers inside the building and the roofers as they install the new roof. By using roof huggers the existing roof can be left in place. The installation of metal roofing is often easier and faster than other roof types and because of its simple design and generally large size can actually be installed directly on top of existing roofing materials like asphalt shingles and foam roofing.

Before you reshingle a roof read our step. This provides added protection against ice dams. You need a flat surface to install a new roof over existing shingles. Beveled wood pieces called horsefeathers must be laid along the thick edges of the shakes to make a fairly flat surface.

The procedure for installing a new roof involves stripping one side of the roof replace old shingles with the new ones and repeat the same process for the other side. That s also why building codes commonly limit re roofing to no more than two layers. Mold rot or other significant damage needs to be taken care of with a full replacement not hidden by new materials. Looks just as good and lasts as long.

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. Asphalt shingles can be laid over cedar shakes or shingles however this is a roofing project best left to pros.