R Values For Roofs

Here are the r values of the most popular commercial roofing systems.

R values for roofs.

It is important to know the r value because many states or regions require that a roof system have a minimum amount of thermal resistance on commercial industrial and or institutional buildings. Always check with your local code authority. The higher the r value the more the material insulates. Know exactly how much you need with our project calculators.

The way it works is simple. R value measures how well certain building insulation materials can resist heat. A material s r value is the measure of its resistance to heat flow. If insulation is compressed its r value is reduced by its compression.

Therefore its r value is reduced by 17 to r 2 1. When determining how much insulation you need don t guesstimate calculate. R value table for roofing materials and building insulation. 6 6 per inch of thickness metal.

Types of roof insulation. 0 24 per inch of thickness. For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1 93721. Insulation with r 2 5 is compressed from 94mm to 78mm i e.

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. To convert rsi to r value multiply the rsi by 5 67826. R value is used as a measurement of the effectiveness of thermal insulating materials. 0 24 per inch of thickness epdm.

The higher the r value the better a material performs as a thermal insulator. 0 34 per inch of thickness bur smooth. Location of r value on a product data sheet.