Minimum Insulation In Roof

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 insulation in roof.

Add insulation to attic. Less than the prescriptive r value at per foot slope as long as the system r value meets or exceeds that. Zone 6 requires an r 30 minimum which is 5 2 thick. 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.

Hitting amazing levels of 0 13w m will need 300mm of mineral wool or 180mm of rigid foam. Minimum insulation r value requirements by state. See the department of energy s doe ranges for recommended levels of insulation below. Recommended insulation levels for retrofitting existing wood framed buildings.

Adhered bituminous membrane minimum requirements adhered single ply membrane minimum requirements see notes below for required perimeter and corner enhancements2 3 2 3see notes below for required perimeter and corner enhancements insulation type thickness 4 x 4 4 x 8 insulation type thickness 4 x 4 4 x 8. Recognized by the iecc. Existing 3 4 inches of insulation. There is an exception provided that allows the minimum thickness to be up to 1.