Two Layers Of Felt On Roof

In northern climates ice or snow dams are another common.

Two layers of felt on 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. Roofing felt offers an additional layer of protection against the elements. Most often made out of plywood this roof layer is installed over the framing in a typical roof install. 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.

Here are the layers of a roof in order of application bottom to top. Before adding the second layer though spread a thin layer of adhesive on the first layer using your trowel. Thus you will repeat the earlier steps. You can cover the surface of the felt with gravel for added strength.

So anywhere along the gable end that you can see the felt you ll see two layers. This will help the two layers adhere to each other. You will follow the same process as in step 2 for the last layer. On 4 12 or greater slopes the balance of the roof shall be one layer of 15 felt.

The first course starts with an extra 1 2 wide run. Cover the edges of the roof with strips of felt before laying out the final layer. Five best practices reasons for using roofing felt underlayment. Add the second layer.

Two layers of shingles trap more heat which in turn damages the shingles and shortens the life span of the roof. Saving on the initial shingle installation doesn t solve the long term cost of adding a second layer of shingles. It provides backup protection in the event of ice or water damage. On roof slopes of 2 12 to 4 12 the remainder of the roof shall be two layers of 15 felt applied in shingle fashion or 1 layer of ice dam protection.

It provides structure by tying. The key to weatherproofing your flat roof is adding a total of 3 layers. If i were you i d at least follow up with that roofer on why they chose to spec 2 layers felt just for piece of mind and in case he turns out to be the better roofer or not. Assuming your roofing contractor is using standard 36 wide 15 roofing felt double coverage means that each layer of felt put down across the roof laps 19 over the upper half of the previous course.

I have been supplied with way too much felt. Wind driven rain or snow can trap water under your shingles putting your roof deck and inner residence at risk of moisture. Apply another layer of adhesive to the top for maximum waterproofing.