Attic Ceiling Insulation R Value

However there is an exception.

Attic ceiling insulation r value.

Achieving greater r values in exterior walls. Recommended insulation levels for retrofitting existing wood framed buildings. 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. Where you live different climates require different insulation r values.

The 2015 irc requires r 49 insulation for ceilings with attic spaces. The higher the r value the better the thermal performance of the insulation. 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. Existing 3 4 inches of insulation.

See the department of energy s doe ranges for recommended levels of insulation below. Your home s age if your home is more than 10 year old you likely need more insulation. While there are additional considerations such as venting and moisture problems to take into account when you insulate under floors the united states department of energy recommends an r 25 rating in cold climates and an r 11 in warmer parts of the country. Pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1.

You will need a higher r value of insulation if you live in the northeast than if you live in southern california. The r value per inch for different types of insulation varies depending on the. 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.