R Value Of Roofing Materials

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 roofing 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. To convert rsi to r value multiply the rsi by 5 67826. The average r value for some common roof materials include. Material r inch r thick ness insulation materials fiberglass batt 3 14.

What are common r values. For a very good introductory overview article on r value see r values over at the website of. There are many websites on the internet which have imperial building material r value numbers but not so many with metric r value numbers. Ft sbs self adhering cap sheet roll for low slope roofing in hickory.

R value of building materials material r inch r thick ness fiberglass inch 3 00 1 inch 4 00. As we said before the r value measures the thermal resistance of a material. It uses the iso thermal planes method the same method as used in nzs4214 2006. This webpage calculates the r value of walls roofs and suspended floors for most insulation material 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. Eps based claddings directly fixed on timber framing. R value is calculated by more than just the insulation. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1 93721.

Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. R value of various materials. To convert the r value of a specific thickness of a material to rsi divide the r value by 5 67826. You should of course see the manufacturer provided technical data sheet for the r value of specific products.

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. 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. Rsi r value système international is the metric equivalent.

Roofing materials asphalt shingles 0 44 wood shingles 0 97 windows single glass 0 91.