Existing 3 4 inches of insulation.
R factor for live in attic.
In most climate zones of the country an attic r value of at least 35 is considered the minimum to meet today s energy conservation goals.
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.
The amount of insulation recommended for your home is dependent on where you live but here are some general guidelines.
Recommended insulation levels for retrofitting existing wood framed buildings.
Houses in a cold climate should have a minimum of r 49 in the attic which is equivalent to approximately 16 of fiberglass insulation.
Therefore at least 11 inches of fiberglass or 9 inches of.
Find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces.
Add insulation to attic.
2x4 walls can hold r 13 or r 15 batts.
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.
Loose fill insulation usually made of fiberglass rock wool or cellulose comes in shreds granules or nodules.
Warmer climates only require an r 38 or higher or about 12 or more.