Minimum Residential Roof Insulation R Value

Insulation that doesn t meet the regulations must be topped up or replaced.

Minimum residential roof insulation r value.

Minimum insulation r value requirements by state. See the department of energy s doe ranges for recommended levels of insulation below. If there s more than one layer of insulation their product r values may be combined. R value measures how well certain building insulation materials can resist heat.

Existing 3 4 inches of insulation. There are many ways to retrofit a home with fiberglass and. When determining how much insulation you need don t guesstimate calculate. You will need a higher r value of insulation if you live in the northeast than if you live in southern california.

Where you live different climates require different insulation r values. 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. Minimum insulation r value requirements non residential above roof deck. 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.

Non residential above roof deck this matrix provides the minimum insulation r values required by local and state municipalities. All insulation must be in reasonable condition. 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. Always double check with your local authority to confirm which code is currently in effect.

Know exactly how much you need with our project calculators. Add insulation to attic. 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. Minimum r values for zones 1 and 2.

By increasing the minimum thermal insulating value for all commercial and high rise residential buildings by 33 percent from r 15 to r 20 building owners could save hearing and cooling costs for the life of their buildings plus reduce dependence on foreign oil which had become a significant issue at the time. Minimum r values for zone 3. Recommended insulation levels for retrofitting existing wood framed buildings. The document was updated in 2020 and is available on the carlisle syntec website.

Your home s age if your home is more than 10 year old you likely need more insulation.