Finished Attic Insulation R Value

Of combined fiberglass and foam insulation.

Finished attic insulation r value. In addition to climate r value also depends on the age of your home. This means you can have a combined r value ranging from r 23 to r 31 with only 5 1 2 in. When determining how much insulation you need don t guesstimate calculate. Your home s age if your home is more than 10 year old you likely need more insulation.

Recommended insulation levels for retrofitting existing wood framed buildings. 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. 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.

Add insulation to attic. The higher the r value the greater the insulation performance. There are many ways to retrofit a home with fiberglass and. 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.

Rigid foam sheeting has an r value ranging from r 5 to r 10 per inch of thickness. For homes in the seattle washington area we ve already established that the correct insulation r value climate zone is 4. You will need a higher r value of insulation if you live in the northeast than if you live in southern california. R value measures how well certain building insulation materials can resist heat.