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.

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. Less than the prescriptive r value at per foot slope as long as the system r value meets or exceeds that. Add insulation to attic. There is an exception provided that allows the minimum thickness to be up to 1.

Achieving a u value of 0 20w m meaning your roof will be better insulated than your walls will need 120mm thickness of rigid foam or 200mm of mineral wool or natural insulation. Minimum insulation r value requirements by state. 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. Hitting amazing levels of 0 13w m will need 300mm of mineral wool or 180mm of rigid foam.

Recommended insulation levels for retrofitting existing wood framed buildings. Minimum insulation r value requirements non residential above roof deck. See the department of energy s doe ranges for recommended levels of insulation below. Zone 6 requires an r 30 minimum which is 5 2 thick.