Two Layers Of Roofing Felt

These applications are ideal for flat roofs or protective surfaces under roof level decks.

Two layers of roofing felt. For decades roofers have fitted a layer of felt over a roof s sheathing or roof deck before installing shingles. In my view two layers of felt atop roof sheathing would not significantly improve the leak resistance of an asphalt shingle low sloped roof. Overlay a second layer of felt 2 to. I have been supplied with way too much felt.

Pros to overlaying a shingle roof. I italicized atop because on very low slope roofs some shingle installation applications specify interlaying a course of felt underlayment perhaps using 30 felt between every shingle course as part of. Steep sloped roof products such as tile slate metal and shakes only allow one layer. For many years it was acceptable to put even the third layer.

Nail metal drip edge flashing which bends over the roof and down the edge of the facing board on all roof edges. Roofing felt offers an additional layer. These thick layers of roofing felt are installed by heating the back of the felt with a butane torch and then carefully applying it to the roof. Though the requirement is 2 layers 15 felt in my area northern california the roofers spec 30 whether for 2 layer low slope or 1 layer normal high slope.

Installing the roofing felt does take care but can go very quickly. Asphalt shingles typically can have one more layer added over the top two roofs total. Installing roof felt is a two person job. Though both these points are valid you will end up spending the same amount of money or more later to.

The main case for adding a second layer of shingles is simplicity. By not removing the first layer of shingles homeowners would be able to save on labor costs and shorten the time frame of the job. Some roofing felts are actually glued down. I am aware of the best practise of at least one layer of underlay nailed to the deck before a cap sheet is glued to the top with cold adhesive.

On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing. Here are the pros and cons. Most building codes allow this but is it a good idea. It didn t come with any underlay but i have worked out i could felt the roof twice with the cap sheet felt they have supplied.

A case for two layers of roof shingles.