Roof Insulation R Value Requirements

The higher the r value the greater the insulation performance.

Roof insulation r value requirements.

Minimum r value non residential above roof deck title. R 38 shall be deemed to satisfy the requirement for r 49 wherever the full height of uncompressed r 38 insulation extends over the wall top plate at the eaves. Pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1. However there is an exception.

Minimum insulation r value requirements non residential above roof deck. 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 by state. R value based method of section c402 1 3 u c and f factor based method of section c402 1 4.

Gables to be insulated as exterior walls. See the department of energy s doe ranges for recommended levels of insulation below. Mandatory minimum r 22 attic insulation unvented attics must be air sealed at roof deck eaves gables and penetrations. When determining how much insulation you need don t guesstimate calculate.

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. R value measures how well certain building insulation materials can resist heat. Know exactly how much you need with our project calculators. Non residential above roof deck this matrix provides the minimum insulation r values required by local and state municipalities.

Recommended insulation levels for retrofitting existing wood framed buildings. Add insulation to attic. These energy code r value requirements change from state to state and even city to city. Existing 3 4 inches of insulation.

Climate zones 1 5 and 8 16 wall assemblies must not exceed a maximum u factor of 0 051 climate zones 6 7 wall assemblies must not exceed a maximum u factor of 0 065. Building and energy codes almost always specify a required minimum r value for exterior walls and roof assemblies with above deck insulation so the minimum required r value in your local jurisdiction is something that you need to take into account when planning a building project. Minimum insulation r value requirements non residential above roof deck. 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.

The 2015 irc requires r 49 insulation for ceilings with attic spaces.