R Value Of Asphalt Roof

Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials.

R value of asphalt roof.

Rsi r value système international is the metric equivalent. As we said before the r value measures the thermal resistance of a material. The percentage increase increase increase original number 100. Roofing materials asphalt shingles 0 44 wood shingles 0 97 windows single glass 0 91 w storm 2 00 double insulating glass inch air space.

Get free shipping on qualified asphalt roof shingles or buy online pick up in store today in the building materials department. R value is used in the united states. To convert rsi to r value multiply the rsi by 5 67826. R3 r18 r21 total roof r value.

R value of various materials. Gaf timbertex pewter gray double layer hip and ridge cap roofing shingles 20 lin. You should of course see the manufacturer provided technical data sheet for the r value of specific products. Labor costs around 2 3 per square foot 200 300 per square and 3 000 4 500 for a 1 500 square foot roof.

Per bundle 30 pieces model 0840552 49 95 bundle 49 95 bundle. R value of building materials material r inch r thick ness fiberglass inch 3 00 1 inch 4 00 inch 6 00. For instance if you have a material with an r value of 12 attached to another material with an r value of 3 then both materials combined have an r value of 15. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1.

Longer lasting options tend to range higher between 11 000 and 14 000. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. For a very good introductory overview article on r value see r values over at the website of. The increase r21 r3 exactly 18 the value by which you are increasing the r value.

The rosemont il based national roofing contractors association nrca recommends that cover boards be used of perlite gypsum board or mineral wool to avoid possible blistering. I calculate insulation resistance to heat loss or r percentage improvement always as relative to the original number. For new roof construction isoboards faced polyisocyanurate insulation are generally used because of their high r value fire resistance and light weight.