Minimum Residential Roof Insulation R Value

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.

Minimum residential roof insulation r value. Minimum insulation r value requirements by state. The higher the r value the greater the insulation performance. The table below shows what levels of insulation are cost effective for different climates and. When determining how much insulation you need don t guesstimate calculate.

Minimum insulation r value requirements non residential above roof deck is an extremely handy table for state and local jurisdictions in the united states. The higher the r value the better the thermal performance of the insulation. 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. R value is a measure of insulation s ability to resist heat traveling through it.

How much insulation does my home need. Recommended home insulation r values. There are many ways to retrofit a home with fiberglass and. Always double check with your local authority to confirm which code is currently in effect.

The document was updated in 2020 and is available on the carlisle syntec website. Insulation level are specified by r value. For the purpose of insulation regulations australia is divided into many different. Know exactly how much you need with our project calculators.

High r value with foam insulation in pennsylvania sprayed polyurethane foam has an aged r value of approximately 6 0 per 1 inch thickness depending on the particular formulation and application higher values have been achieved enabling it to provide more thermal resistance with less material than any other type of commercial insulation. Non residential above roof deck this matrix provides the minimum insulation r values required by local and state municipalities. Injection foam insulation s higher r value with an r value of 4 0 to 5 1 per inch depending on the manufacturer pre expanded injection foam provides a higher r value than fiberglass or cellulose and it seals the building from air leakage at the same time. The regulations in the building code of australia bca that apply to home insulation are complicated.

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. What r value do i need. Your home s age if your home is more than 10 year old you likely need more insulation. You will need a higher r value of insulation if you live in the northeast than if you live in southern california.

R value measures how well certain building insulation materials can resist heat.