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.

Ft sbs self adhering cap sheet roll for low slope roofing in hickory. Roofing materials asphalt shingles 0 44 wood shingles 0 97 windows single glass 0 91. 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. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826.

Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. For a very good introductory overview article on r value see r values over at the website of. Material r inch r thick ness insulation materials fiberglass batt 3 14. Rsi r value système international is the metric equivalent.

The following table is in metric form. 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. There are many websites on the internet which have imperial building material r value numbers but not so many with metric r value numbers. R value of building materials material r inch r thick ness fiberglass inch 3 00 1 inch 4 00.

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. R value is calculated by more than just the insulation. Eps based claddings directly fixed on timber framing. 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.

R value of various materials. It uses the iso thermal planes method the same method as used in nzs4214 2006. You should of course see the manufacturer provided technical data sheet for the r value of specific products. Some of the possible material combinations may not be suitable for actual constructions i e.

For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1 93721. To convert rsi to r value multiply the rsi by 5 67826. As we said before the r value measures the thermal resistance of a material. The average r value for some common roof materials include.

These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation.