Finished Attic Insulation R Value

R value measures how well certain building insulation materials can resist heat.

Finished attic insulation r value.

Recommended insulation levels for retrofitting existing wood framed buildings. Install air chutes before installing insulation why your roof needs air chutes. You will need a higher r value of insulation if you live in the northeast than if you live in southern california. 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.

If you look at the chart above you can see that the attic should achieve an r value between r 38 and r 60 depending on the current insulation levels. Your home s age if your home is more than 10 year old you likely need more insulation. Of combined fiberglass and foam insulation. Depending on where you live and the part of your home you re insulating walls crawlspace attic etc you ll need a different r value.

Existing 3 4 inches of insulation. This means you can have a combined r value ranging from r 23 to r 31 with only 5 1 2 in. Where you live different climates require different insulation r values. For homes in the seattle washington area we ve already established that the correct insulation r value climate zone is 4.

Add insulation to attic. The higher the r value the greater the insulation performance. Rigid foam sheeting has an r value ranging from r 5 to r 10 per inch of thickness. When determining how much insulation you need don t guesstimate calculate.