Minimum R Value For Roof 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.

Minimum r value for roof insulation.

Know exactly how much you need with our project calculators. 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 insulation levels for retrofitting existing wood framed buildings. 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. 2015 code requires walls to be insulated with a minimum of r 20 or r 13 5 13 5 means r 13 cavity insulation plus r 5 insulated sheathing. The higher the r value the greater the insulation performance. Since a tapered insulation system will increase thickness away from the low points the overall system r value will.

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 by state. Existing 3 4 inches of insulation. R value measures how well certain building insulation materials can resist heat.

The r values shown above are the minimum r values required to meet code requirements. How does this affect r values on a tapered insulation system. The document was updated in 2020 and is available on the carlisle syntec website. See the department of energy s doe ranges for recommended levels of insulation below.

Minimum insulation r value requirements non residential above roof deck. R 20ci r 25ci r 25ci r 30ci r 30ci r 30ci r 35ci r 35ci question.