Let s say the insulation you ve selected has an r value of three per inch and you d like to achieve an overall value of r 36.
Attic insulation rating.
Add insulation to attic.
Multiply the length times the width to determine the square footage of the space.
If your current insulation is only 5 inches deep you ll need to add seven inches of insulation to achieve the 12 inch r 38 rating.
See the department of energy s doe ranges for recommended levels of insulation below.
Measure the length and width of the area you need to insulate.
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.
If your insulation doesn t measure up and you need more installation can be done as a weekend diy project or you can call a professional installer to handle the job.
An r value tells you how well a type of insulation can keep heat from leaving or entering your home.
Recommended insulation levels for retrofitting existing wood framed buildings.
Measure the area needing insulation.
You ll need about 12 inches of insulation material.
Insulation r values vary based on the type thickness and density of the insulation material.
Your attic should have a certain amount of insulation in it and the recommended level of insulation for your attic is dependent on where you live.
Existing 3 4 inches of insulation.