Minimum R Value For Attic

The higher the r value the better the thermal performance of the insulation.

Minimum r value for attic.

With an r value of 4 0 to 5 1 per inch depending on the manufacturer pre expanded injection foam provides a higher r value than fiberglass or cellulose and it seals the building from air leakage at the same time. In zone 2 the average minimum requirement for attic insulation is 9 inches of r30 fill. When determining how much insulation you need don t guesstimate calculate. R value measures how well certain building insulation materials can resist heat.

Find out why in the seller s fact sheet on r values. R value is a measure of insulation s ability to resist heat traveling through it. R value is a measure of insulation s ability to resist heat flow. If structural sheathing covers 40 or less of the exterior continuous insulation r value shall be permitted to be reduced by no more than r 3 in the locations where structural sheathing is used to maintain a consistent total sheathing thickness.

R values for walls represent the sum of cavity insulation plus insulated sheathing if any. Know exactly how much you need with our project calculators. In zone 1 the average minimum requirement for attic insulation is 9 inches of r30 fill. The recommended level for most attics is to insulate to r 38 or about 10 to 14 inches depending on insulation type.

Insulation level are specified by r value. The average recommended level is 14 inches of r49. Usually the recommended r value for attics varies between r 40 and r 80 depending on the area province and climate. The higher the r value the better the thermal performance of the insulation.

The higher the r value the greater the insulation performance. Consequently the thickness which fluctuates according to the type of insulating material must be suitable to meet the needs of 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. 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.

Insulation r values are minimum acceptable levels and must be determined according to ftc rule. Under insulated here means when compared to the minimum prescriptive wall and ceiling insulation r values found in the 2006 international energy conservation code iecc savings vary.