How To Count Roof Layers

The roofer simply put plywood over a 5 layer roof and put a new layer of shingles over that.

How to count roof layers. Enter the extension wall length into wall length and double the extension wall width then minus ridge thickness into the wall width entries. On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing. R value of various materials. My dad ended up landing the job.

Asphalt shingles typically can have one more layer added over the top two roofs total. He had gotten about 3 4 of the way through the job before the city shut them down. You can usually see the underside of plywood decking from the attic. Outside of the u s a degree angle is typically used.

We have done some 5 layer tear offs redecks. For a very good introductory overview article on r value see r values over at the website of. Find the square footage of the roof. Second layer was plywood over tin and shingles installed.

It provides structure by tying the trusses and joists together. You should of course see the manufacturer provided technical data sheet for the r value of specific products. Here are the layers of a roof in order of application bottom to top. First layer was the original tin roof.

If you have a simple gable roof you ll only need to measure and sum up the 2 planes of the roof. Steep sloped roof products such as tile slate metal and shakes only allow one layer. Needless to say we declined the job due to excessive cost and restructuring the roof. Measure the length and width of each portion of the roof multiply length by width for each plane and then add the planes together for the total square footage.

Finally the forth layer was wood shakes not kidding it was crazy. There is a base wood shake layer and the asphalt shingle layers. Minus ridge thickness to allow for ridge becoming pole plate roof peak will be slightly higher ridge thick must be same. Porch roof extensions for hip roof porch extensions from an existing building wall you can use half the calculator results.

Third layer was another layer of asphalt shingles. My dad has said to have done 7 layer tear offs. For instance a 7 12 roof pitch means that the roof rises 7 inches for every 12 horizontal inches. Decking most often made out of plywood this roof layer is installed over the framing in a typical roof install.

This gives us a 3d roof area of 1 625 sq ft. If you are knowledgeable in being able to calculate from this view it would be hugely helpful. Assuming this is a hip roof we multiply this by 1 1 which gives us roughly 18 squares or 1 800 square feet of the roof surface. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials.

For estimating purposes we also assume that there is a chimney a couple of dormers and two layers of old shingles that need to be torn off and removed before a new roof can be installed.