Gaf Torchdown Overtop An Existing One Layer 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.

Gaf torchdown overtop an existing one layer roof. How to install a roof over an existing roof. There are two different types of torch down roofing systems. Depending on your roofing systems design one of these membranes might be a better choice than the other. A two layer system is made up of one base layer and one torch down layer.

The membrane is available with a smooth surface. Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option. Its core is a strong resilient non woven polyester mat that is coated with weather resistant app polymer modified asphalt. There are many choices and material types you can use on your flat roofing system in seattle.

Installed roof designs weigh less than 2 pounds per square foot ruberoid torch granule membrane polyester mat core allows it to resist splits. The installed cost of ruberoid torch granule membrane is less than most single ply systems on the market today. Two layer torch down roofing may cost less. 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.

Plus learn the advantages and disadvantages of a torch down roof system. However installing new flashings including special drip edge flashings made for reroofing will ensure a tight seal and a long life. Discover the various components of a torch down roof and the materials used to manufacture it. Typical system guarantees available for up to 15 years.

Single ply membranes such as pvc epdm tpo or torchdown also known modified bitumen are the most common low slope and flat roofing materials. Two layer and three layer torch down roof systems. Torch down roofs are composed of two or more layers of a modified asphalt membrane applied with an open flame torch. This provides added protection against ice dams.

Select system constructions available with up to 20 year guarantee coverage 1. Three layer systems have a base a smooth torch down layer and a torch down layer with a granular surface. A three layer torch down roof features the same base and cap sheets as well as an additional cap sheet with a granulated surface. Two layer systems tend to last approximately 15 years while three layer torch down roofing can last 20 years or longer.

Advantages of three layer torch down roofing. A two layer torch down roof consists of one base sheet and one smooth cap sheet.