Minimum Residential Roof Insulation R Value

State applicable energy ashrae zone minimum r value state local ms mississippi ashrae 90 1 2010 2r 20 3r 20 state local mo missouri 2012 iecc 4r 25 5r 25 state only mt montana 2012 iecc 6 r 30.

Minimum residential roof insulation r value.

R value is a measure of insulation s ability to resist heat traveling through it. Insulation level are specified by r value. Less than the prescriptive r value at per foot slope as long as the system r value meets or exceeds that. Minimum insulation r value requirements non residential above roof deck.

In a cold climate you need an r value of 49. While not part of the building regulations there is an unwritten rule of how high an r value you need. 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. There is an exception provided that allows the minimum thickness to be up to 1.

Zone 6 requires an r 30 minimum which is 5 2 thick. England new dwellings. Minimum insulation r value requirements non residential above roof deck is an extremely handy table for state and local jurisdictions in the united states. Non residential above roof deck this matrix provides the minimum insulation r values required by local and state municipalities.

The document was updated in 2020 and is available on the carlisle syntec website. 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. Recommended home insulation r values. Minimum insulation r value requirements by state.

Our guides to building regulations in england adl1a 2013 building regulations. The r value is the thermal efficiency of your product. A u value of 0 55 w m k is used for cavity insulation and 0 30 w m k for internal or external wall insulation. Recognized by the iecc.