Minimum Roof Insulation R Value

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

Minimum roof insulation r value.

The higher the r value the better the thermal performance of the insulation. Non residential above roof deck this matrix provides the minimum insulation r values required by local and state municipalities. R value measures how well certain building insulation materials can resist heat. 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. R value is a measure of insulation s ability to resist heat traveling through it. 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.

If you think you re among the 90 of us homes that are under insulated 1 performing a simple insulation inspection will help you determine your insulation needs. The terminology average r value for tapered systems is an outdated term and not recognized by the iecc. Know exactly how much you need with our project calculators. Having the correct amount of attic insulation can help you maintain a comfortable temperature throughout your home and help save money on your energy bills plus prevent major issues like ice dams in the winter.

There is an exception provided that allows the minimum thickness to be up to 1 less than the prescriptive r value at per foot slope as long as the system r value meets or exceeds that prescriptive r value. With the widest range of faced laminated and standard high performance eps insulation products insulfoam has the right products for your needs while still providing the highest r value per dollar over. Minimum insulation r value requirements non residential above roof deck is an extremely handy table for state and local jurisdictions in the united states. Minimum insulation r value requirements non residential above roof deck.

Minimum insulation r value requirements by state. Specific insulation requirements of section c402 2 thermal requirements of either. Or component performance alternative of section c402 1 5 roof solar reflectance and thermal emittance fenestration in building envelope. When determining how much insulation you need don t guesstimate calculate.

The higher the r value the greater the insulation performance.