R Value Of Roofing Materials

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.

R value of roofing materials. Click here to go to our calculator to understand the real r value of a ceiling system or wall system with gaps in the insulation. The average r value for some common roof materials include. Some of the possible material combinations may not be suitable for actual constructions i e. Roofing materials asphalt shingles 0 44 wood shingles 0 97 windows single glass 0 91.

The following table is in metric form. For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3. You should of course see the manufacturer provided technical data sheet for the r value of specific products. R value of various materials.

Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1 93721. Ft sbs self adhering cap sheet roll for low slope roofing in hickory. Additional r value for a masonry wall constructed using these materials needs to add the insulating value of additional wall components typically included such as 1 solid foam polyisocyanurate r 8 extruded polystyrene r 5 expanded polystyrene r 4 or 1 of perlite r 2 7 and for an exterior air film winter no wind r 0 17 an interior.

It uses the iso thermal planes method the same method as used in nzs4214 2006. To convert rsi to r value multiply the rsi by 5 67826. To calculate the r value of a roof system your contractor will take into account the underlayment coverboards adhesives insulation and even the membrane. R value of building materials material r inch r thick ness fiberglass inch 3 00 1 inch 4 00.

R value is calculated by more than just the insulation. There are many websites on the internet which have imperial building material r value numbers but not so many with metric r value numbers. This webpage calculates the r value of walls roofs and suspended floors for most insulation material r values. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826.

Rsi r value système international is the metric equivalent. What are common r values. Torch down roofing peel and stick roofing asphalt roll roofing low slope roll roofing roll roofing mineral surface rolled roofing roll roofing roofing materials related products liberty 3 ft. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation.

Material r inch r thick ness insulation materials fiberglass batt 3 14.