Minimum R Value For Attic

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.

Minimum r value for attic.

When determining how much insulation you need don t guesstimate calculate. Usually the recommended r value for attics varies between r 40 and r 80 depending on the area province and climate. In zone 1 the average minimum requirement for attic insulation is 9 inches of r30 fill. 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.

R value measures how well certain building insulation materials can resist heat. 2015 code requires walls to be insulated with a minimum of r 20 or r 13 5 13 5 means r 13 cavity insulation plus r 5 insulated sheathing. R values for walls represent the sum of cavity insulation plus insulated sheathing if any. 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.

In zone 2 the average minimum requirement for attic insulation is 9 inches of r30 fill. The second r value for mass walls applies when more than half the insulation is on the interior of the mass wall. 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. Consequently the thickness which fluctuates according to the type of insulating material must be suitable to meet the needs of r value.

Insulation r values are minimum acceptable levels and must be determined according to ftc rule. The average recommended level is 14 inches of r49. The higher the r value the better the thermal performance of the insulation. Insulation level are specified by r value.

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. The higher the r value the better the thermal performance of the insulation. R value is a measure of insulation s ability to resist heat traveling through it. Find out why in the seller s fact sheet on r values.

The higher the r value the greater the insulation performance. Recommended home insulation r values.