Attic Insulation R Value Code

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

Attic insulation r value code.

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. You can achieve better thermal performance in your attic by adding an additional layer of insulation. Insulation level are specified by r value. R value is a measure of insulation s ability to resist heat traveling through it.

Energy star states that an r 60 is equal to the best performing attic insulation. There are many ways to retrofit a home with fiberglass and. Your home s age if your home is more than 10 year old you likely need more insulation. However if an r 38 was enough customers wouldn t ask why they re still too cold or hot in their home.

The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. 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. In general to optimally isolate an attic on average an r value of the insulation is required ranging from r 50 to r 60.

For an attic the you could have an r 38 to meet the insulation code guidelines. Where you live different climates require different insulation r values. Achieving greater r values in exterior walls. 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.

The table below shows what levels of insulation are cost effective for different climates and. These r values are a sum meaning this should be the total r value once you add up the entire depth of 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. Recommended home 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. Dte energy and consumers energy suggest an r 49 or above to be energy efficient. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.