Finished Attic Insulation R Value

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.

Finished attic insulation r value.

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. The higher the r value the greater the insulation performance. Of combined fiberglass and foam insulation.

Recommended insulation levels for retrofitting existing wood framed buildings. There are many ways to retrofit a home with fiberglass and. Add insulation to attic. This means you can have a combined r value ranging from r 23 to r 31 with only 5 1 2 in.

If the existing attic floor insulation has an r 11 insulation value then an additional r 27 would be needed to bring the attic floor insulation up to the level recommended for that house. But the roof is a major pathway to heat loss and gain so it s worth shelling out the extra bucks for spray foam. It forms a much tighter air barrier and you ll get the same r value with fewer inches of the stuff so you ll have extra room overhead. It costs two to three times more than fiberglass batt insulation.

Let s say the insulation you ve selected has an r value of three per inch and. The recommended r value for attic floor insulation for this house is r 38. Existing 3 4 inches of insulation. Know exactly how much you need with our project calculators.

In particularly cold climates you might go up to r 60. However there is an exception. When determining how much insulation you need don t guesstimate calculate. For homes in the seattle washington area we ve already established that the correct insulation r value climate zone is 4.

Zone the area under a. R 38 shall be deemed to satisfy the requirement for r 49 wherever the full height of uncompressed r 38 insulation extends over the wall top plate at the eaves. Rigid foam sheeting has an r value ranging from r 5 to r 10 per inch of thickness. Where you live different climates require different insulation r values.

In addition to climate r value also depends on the age of your home. Lighter in weight than cellulose or mineral wool but it settles more than those materials so you ve got to put in a thicker layer to get the protection you need. Your home s age if your home is more than 10 year old you likely need more insulation. R value measures how well certain building insulation materials can resist heat.

Pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1. The homeowner could then check table 1 to find several choices.