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.

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. 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.

R 20ci r 25ci r 25ci r 30ci r 30ci r 30ci r 35ci r 35ci question. Add insulation to attic. Minimum insulation r value requirements by state. Minimum insulation r value requirements non residential above roof deck.

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

See the department of energy s doe ranges for recommended levels of insulation below. The r values shown above are the minimum r values required to meet code requirements. Since a tapered insulation system will increase thickness away from the low points the overall system r value will. 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 is an extremely handy table for state and local jurisdictions in the united states. Existing 3 4 inches of insulation.