Minimum R Value For Attic Insulation

Meet minimum r values given in table 402 1 1 frame walls r 13 block walls interior insulation r 7 8 exterior insulation r 6 ceilings.

Minimum r value for attic insulation.

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. Prescriptive compliance form 405. Insulation levels are specified by r value. When determining how much insulation you need don t guesstimate calculate.

Add the right kind of insulation. 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. Performance compliance walls ceilings floors. Recommended home insulation r values.

In general to optimally isolate an attic on average an r value of the insulation is required ranging from r 50 to r 60. R value is a measure of insulation s ability to resist heat traveling through it. In zone 2 the average minimum requirement for attic insulation is 9 inches of r30 fill. R value measures how well certain building insulation materials can resist heat.

How much insulation in attic for zones 1 4. Your home s age if your home is more than 10 year old you likely need more insulation. Maximum 20 of conditioned floor area. There are many ways to retrofit a home with fiberglass and.

The average recommended level is 17 inches of r60. Ceiling insulation must be much higher at r 30 and a raised floor must be at least r 13. In zone 1 the average minimum requirement for attic insulation is 9 inches of r30 fill. Insulating power or r value is only one factor to consider when building or improving a home to keep it comfortable.

Where you live different climates require different insulation r values. You will need a higher r value of insulation if you live in the northeast than if you live in southern california. 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. The higher the r value the greater the insulation performance.

Know exactly how much you need with our project calculators. Raised r 13 sog r 0 windows. The higher the r value the better the thermal performance of the insulation. The insulation levels of an attic or of any part of a house are understood through the r value that is the value with which the insulating material is resistant to heat flow.

The table below shows what levels of insulation are cost effective for different climates and. Insulation level are specified by r value. For block walls interior insulation must meet or exceed r 7 8 and exterior insulation must be r 6. The average recommended level is 14 inches of r49.

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