Minimum R Value For Attic

Insulation level are specified by r value.

Minimum r value for attic. 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 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 is a measure of insulation s ability to resist heat flow.

The recommended level for most attics is to insulate to r 38 or about 10 to 14 inches depending on insulation type. 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. The higher the r value the better the thermal performance of the 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.

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 greater the insulation performance. In zone 2 the average minimum requirement for attic insulation is 9 inches of r30 fill. The average recommended level is 14 inches of r49.

The higher the r value the better the thermal performance of the insulation. R value measures how well certain building insulation materials can resist heat. When determining how much insulation you need don t guesstimate calculate. Know exactly how much you need with our project calculators.

Consequently the thickness which fluctuates according to the type of insulating material must be suitable to meet the needs of r value. R values for walls represent the sum of cavity insulation plus insulated sheathing if any. Recommended home insulation r values. Insulation r values are minimum acceptable levels and must be determined according to ftc rule.

Find out why in the seller s fact sheet on r values. 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.