Roof R Value

To calculate the r value of a roof system your contractor will take into account the underlayment coverboards adhesives insulation and even the membrane.

Roof r value.

Typical recommendations for exterior walls are r 13 to r 23 while r 30 r 38 and r 49 are common for ceilings and attic spaces. 0 33 per inch of thickness. 0 34 per inch of thickness. Insulation level are specified by r value.

The percentage increase increase increase original number 100. The terminology average r value for tapered systems is an outdated term and not recognized by the iecc. Recommended home insulation r values. The following table provides typical r values and rsi for various materials these r values were taken from manufacturer technical data sheets and are the reported r values per inch of actual products.

R value is a measure of insulation s ability to resist heat traveling through it. 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. The higher the r value the more the material insulates. The average r value for some common roof materials include.

6 6 per inch of thickness. Higher r value means greater insulation performance and thus more savings on your next heating and cooling bill. Here are the r values of the most popular commercial roofing systems. For each different material multiply the thickness by the standard r value per inch for that material.

The table below shows what levels of insulation are cost effective for different climates and locations in the home. A material s r value is the measure of its resistance to heat flow. This guide will teach you everything you need to know about insulation r values so you can better insulate your home. 0 24 per inch of thickness.

R value measures how well building insulation can prevent the flow of heat into and out of the home. R3 r18 r21 total roof r value. To learn more about r value see roof online s r value page. 0 24 per inch of thickness.

The higher the r value the better the thermal performance of the insulation. I calculate insulation resistance to heat loss or r percentage improvement always as relative to the original number. The way it works is simple. Add the results for all the materials together to get the total r value for the roof assembly.

There is an exception provided that allows the minimum thickness to be up to 1 less than the prescriptive r value at per foot slope as long as the system r value meets or exceeds that prescriptive r value. To calculate the total r value of a roof assembly find the total thickness in inches of each type of insulating material within the system.