15 Roofing Felt R Value

The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process.

15 roofing felt r value.

If the slope is between 3 12 and 4 12 use two layers of 15 felt for asphalt shingles. The 15 pound was for lighter weight projects while the 30 offered more heavy duty protection. For many years roofers used asphalt saturated felt under roofing shingles and it was historically available in two standard weights. 0 05 wood 0 94 metal any 0 00 ceramic tile in.

Roofing r value per inch r v per unit roofing felt 0 06 asphalt roll 90 lb 0 15 asphalt shingle 0 44 slate in. If the slope is greater than 4 12 which provides more water drainage from the roof use one layer of 15 felt. R3 r18 r21 total roof r value. I calculate insulation resistance to heat loss or r percentage improvement always as relative to the original number.

Organic dry felt is made from 100 post consumer recycled material. Calculate percent improvement in r value. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. 0 20 siding r value per inch r v per unit wood shingles 16in.

The increase r21 r3 exactly 18 the value by which you are increasing the r value. 15 pounds per hundred square feet and 30 pounds per hundred square feet.