Minimum Insulation In Roof

Recommended insulation levels for retrofitting existing wood framed buildings.

Minimum insulation in roof.

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. Add insulation to attic. 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.

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. Less than the prescriptive r value at per foot slope as long as the system r value meets or exceeds that. Non residential above roof deck this matrix provides the minimum insulation r values required by local and state municipalities. 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.

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. There is an exception provided that allows the minimum thickness to be up to 1. Recognized by the iecc. Minimum insulation r value requirements by state.