Roof Membrane R Value

What are common r values.

Roof membrane r value.

1 000 sq ft 500 sq ft. R oll s ize n ote. Gaf analyzed membrane samples from roofs across the us and studied thickness over scrim surface cracking and the ability to repair aging tpo membranes. The u value includes the thermal resistance values for roofing and both inside and outside air films in addition to the insulation material.

Always check with your local code authority. For example while optimum performance using a black membrane the assembly must utilize insulation with an r value of 29. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. Please note that the r values for roof membranes shingles tiles air films and roof deck materials might or might not be permitted by your local code to be included when total roof assembly r value is being calculated for the purpose of satisfying energy code requirements.

R value of various materials. The membrane is attached using 12 o c. Roof membrane available in 40 50 and 60 mil thickness. A u value incorporates the total system approach to insulation design.

Extruded expanded polystyrene insulation is commonly used in inverted roof membrane assemblies irma. To calculate the r value of a roof system your contractor will take into account the underlayment coverboards adhesives insulation and even the membrane. Sprayed polyurethane foam spf will have an r value of 7 14 when it is newly installed. Both types have an r value ranging from 4 r to 6 r per 1 inch of insulation thickness.

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. Pattern with perimeter sheets attached 6 o c. 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 tables show a u value r value and c value for several thicknesses of siplast roof insulation systems.

For a very good introductory overview article on r value see r values over at the website of. R value is calculated by more than just the insulation. 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. The amount shown is an average amount used for roof system r value calculations.

Quite the contrary in colder regions ashrae zones 4 through 8. Single ply roofing information. You should of course see the manufacturer provided technical data sheet for the r value of specific products. For white and black membranes the table outlines the necessary adjustments in r values to maintain a roof assembly s energy performance.