Membrane Roof R Value

R value of various materials.

Membrane roof r value.

After it ages a few months the r value will reduce to somewhere around 6 88. Common flat roof membranes discussed in this article include built up asphalt tar and gravel modified bitumen and single ply membranes like epdm pvc tpo and kee. To calculate the r value of a roof system your contractor will take into account the underlayment coverboards adhesives insulation and even the membrane. The average r value for some common roof materials include.

For example while optimum performance using a black membrane the assembly must utilize insulation with an r value of 29. Both types have an r value ranging from 4 r to 6 r per 1 inch of insulation thickness. We also cover spray applied foam and liquid roofing options. 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.

Table 1 shows r values for siplast roof insulation materials and other insulation materials. Roof membrane available in 40 50 and 60 mil thickness. Commonly used in inverted roof membrane assemblies irma. R 1 k factor.

Sprayed polyurethane foam spf will have an r value of 7 14 when it is newly installed. Single ply roofing information. Always check with your local code authority. Quite the contrary in colder regions ashrae zones 4 through 8.

The r value is expressed as r per inch for design purposes. Pattern with perimeter sheets attached 6 o c. For a very good introductory overview article on r value see r values over at the website of. The membrane is attached using 12 o c.

Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. Membrane roofing is often used on commercial flat roofs. You should of course see the manufacturer provided technical data sheet for the r value of specific products. The r value or thermal resistance value is determined from the above test measurements using the formula.