15 Roofing Felt R Value

Organic dry felt is made from 100 post consumer recycled material.

15 roofing felt r value.

0 05 wood 0 94 metal any 0 00 ceramic tile in. 0 87 wood drop 1in. 15 astm 4869 type i is an authentic 15 astm 4869 type i is an authentic asphalt saturated organic felt underlayment is used as a breathable secondary weather resistant barrier when applied over the roof deck prior to the installation of the primary roofing product. If the slope is between 3 12 and 4 12 use two layers of 15 felt for asphalt shingles.

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. The increase r21 r3 exactly 18 the value by which you are increasing the r value. I calculate insulation resistance to heat loss or r percentage improvement always as relative to the original number. 15 pounds per hundred square feet and 30 pounds per hundred square feet.

Calculate percent improvement in r value. The 15 pound was for lighter weight projects while the 30 offered more heavy duty protection. R3 r18 r21 total roof r value. If the slope is greater than 4 12 which provides more water drainage from the roof use one layer of 15 felt.

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. For many years roofers used asphalt saturated felt under roofing shingles and it was historically available in two standard weights.