Roof Membrane R Value

A u value incorporates the total system approach to insulation design.

Roof membrane r value.

R value is calculated by more than just the insulation. The u value includes the thermal resistance values for roofing and both inside and outside air films in addition to the insulation material. For a very good introductory overview article on r value see r values over at the website of. Extruded expanded polystyrene insulation is commonly used in inverted roof membrane assemblies irma.

5 x 100 128 lbs. For white and black membranes the table outlines the necessary adjustments in r values to maintain a roof assembly s energy performance. Both types have an r value ranging from 4 r to 6 r per 1 inch of insulation thickness. You should of course see the manufacturer provided technical data sheet for the r value of specific products.

P roduct sizes dim ensions and w idths are nom inal values and are subject to norm al m anufacturing packaging tolerance and variation c olors f u ll r oll s ize f u ll r oll w eigh t h alf r oll s ize h alf r oll w eigh t w hite t an g ray 10 x 100 256 lbs. R value of various materials. Gaf analyzed membrane samples from roofs across the us and studied thickness over scrim surface cracking and the ability to repair aging tpo membranes. Roof membrane available in 40 50 and 60 mil thickness.

Quite the contrary in colder regions ashrae zones 4 through 8. Duro last 50 mil membrane is manufactured with 28 mil of thickness on the top performance layer far exceeding industry standards as well as competitor systems with equal and even greater mil values. The amount shown is an average amount used for roof system r value calculations. Sprayed polyurethane foam spf will have an r value of 7 14 when it is newly installed.

To calculate the r value of a roof system your contractor will take into account the underlayment coverboards adhesives insulation and even the membrane. Mechanically attached installation uses heavy duty screws and barbed plates to hold the membrane down tightly and is not affected by possible iso de lamination. The membrane is attached using 12 o c. Always check with your local code authority.

What are common r values. 1 000 sq ft 500 sq ft. The average r value for some common roof materials include. R oll s ize n ote.

Single ply roofing information. For example while optimum performance using a black membrane the assembly must utilize insulation with an r value of 29. Pattern with perimeter sheets attached 6 o c. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials.