In temperate coastal areas such as zone 3 attic insulation of at least r30 up to a maximum of r60 is recommended.
Standard depth of blown in fiberglass insulation attic.
For loose fill cellulose this translates to a total depth ranging from 8 inches.
Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation.
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.
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.
I wanted an r value between 49 and 60 in my attic so i settled upon a desired depth of twenty inches of insulation.
First things first you need to go up into your attic inspect the condition of the insulation and calculate the current level of insulation.
This calculator is to be used as an estimating tool only.
Ten inches of blown insulation provides an insulating value of approximately r 30 1 inch of fiberglass provides about r 2 7 while 1 inch of cellulose is approximately r 3.
Each bag of fiberglass insulation will cover approximately 65 square feet of attic space to a depth of 10 inches cellulose insulation covers half as much.
Cellulose attic insulation read more.
Click the button to calculate the approximate r value for this job.
When blown into attics and wall spaces loose fill fiberglass offers an average r 2 5 thermal value per inch the higher the number the greater the insulating effect.
Inspecting your attic insulation.
Fibreglass insulation material has no nutritional value for insects and less likely to get attacked by them.
Input depth of existing blown in insulation in inches.
To ensure an even distribution i cut a dozen dowel rods to match that depth and then spray painted their top halves a bright orange color.
This type of insulation comes in two types of densities medium and high which translates into an r 11 and r 15 for a standard 2x4 wall.
Attic insulation is a key to saving energy during the heating season.
To arrive at r 38 you need at least 15 2 inches of blown in fiberglass insulation requiring you to add 3 2 more inches of insulation if you already have 12.
For instance if you have fiberglass insulation in your attic 12 inches deep the insulation has an r value of 30.