R Value Roof Membrane

Location of r value on a product data sheet.

R value roof membrane.

After it ages a few months the r value will reduce to somewhere around 6 88. The average r value for some common roof materials include. Always check with your local code authority. For white and black membranes the table outlines the necessary adjustments in r values to maintain a roof assembly s energy performance.

For example while optimum performance using a black membrane the assembly must utilize insulation with an r value of 29. Types of roof insulation. The membrane is attached using 12 o c. 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. 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 table for roofing materials and building insulation. In simple terms r values measure the effectiveness of insulation and a higher number represents more effective insulation.

Pattern with perimeter sheets attached 6 o c. Sprayed polyurethane foam spf will have an r value of 7 14 when it is newly installed. Olson has calculated the percent reduction from design r value to be up to 29 percent. Roof insulation design generally when a designer specifies an insulation he or she may request that the roof insulation provide a minimum r value or when a sloped system is installed that the insulation meet an average r value.

Gaf analyzed membrane samples from roofs across the us and studied thickness over scrim surface cracking and the ability to repair aging tpo membranes. Quite the contrary in colder regions ashrae zones 4 through 8. Effective r value the fasteners used to attach insulation boards and single ply membranes act as thermal bridges so that the design r value is reduced to an effective r value. In construction the r value is the measurement of a material s capacity to resist heat flowfrom one side to the other.

The higher the r value the better a material performs as a thermal insulator. Both types have an r value ranging from 4 r to 6 r per 1 inch of insulation thickness.