R Value Of Roofing Materials

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 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. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. It uses the iso thermal planes method the same method as used in nzs4214 2006. 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.

You should of course see the manufacturer provided technical data sheet for the r value of specific products. To convert rsi to r value multiply the rsi by 5 67826. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. 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. The average r value for some common roof materials include. R value of various materials. 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.

Roofing materials asphalt shingles 0 44 wood shingles 0 97 windows single glass 0 91. As we said before the r value measures the thermal resistance of a material. To calculate the r value of a roof system your contractor will take into account the underlayment coverboards adhesives insulation and even the membrane. 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.

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. The following table is in metric form. R value is calculated by more than just the insulation. Eps based claddings directly fixed on timber framing.

Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. Rsi r value système international is the metric equivalent. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1 93721. Some of the possible material combinations may not be suitable for actual constructions i e.

Ft sbs self adhering cap sheet roll for low slope roofing in hickory.