Minimum Insulation In Roof

Non residential above roof deck this matrix provides the minimum insulation r values required by local and state municipalities.

Minimum insulation in roof.

Existing 3 4 inches of insulation. 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. 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.

See the department of energy s doe ranges for recommended levels of insulation below. Add insulation to attic. Recognized by the iecc. Hitting amazing levels of 0 13w m will need 300mm of mineral wool or 180mm of rigid foam.

Less than the prescriptive r value at per foot slope as long as the system r value meets or exceeds that. 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. 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. Minimum insulation r value requirements non residential above roof deck.