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.

Hunter panels roofing tech topic r105. Recommended levels of insulation. Recommended insulation levels for retrofitting existing wood framed buildings. Basement walls require a minimum of either r 10 continuous or r 13 batted 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. When determining how much insulation you need don t guesstimate calculate. Existing 3 4 inches of 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 to maintain a consistent total sheathing thickness.

Add insulation to attic. The document was updated in 2020 and is available on the carlisle syntec website. Minimum insulation r value requirements non residential above roof deck. Non residential above roof deck this matrix provides the minimum insulation r values required by local and state municipalities.

You will need a higher r value of insulation if you live in the northeast than if you live in southern california. The higher the r value the greater the insulation performance. There are many ways to retrofit a home with fiberglass and mineral wool insulation. Your home s age if your home is more than 10 year old you likely need more insulation.

Total minimum ratings to provide 1 75 btu or 0 50 watts per ft2 of conditioned floor area or provide 3 of energy used for mechanical and swh equipment and lighting dedicated outdoor air system per c406 6 or be equipped with an independent ventilation system designed to provide 100 outdoor air to each occupied space. R value measures how well certain building insulation materials can resist heat. Minimum insulation r value requirements by state. Know exactly how much you need with our project calculators.

Zone 6 requires an r 30 minimum which is 5 2 thick.