How Thick Should Blown Insulation Be In Attic

The higher the r value the better the thermal performance of the insulation.

How thick should blown insulation be in attic.

This flexible insulation material is most often packaged in rolls that come in various thicknesses and standard widths usually 16 inches and 24 inches to fit between joists or studs in a house s framing. They come with or without a paper or foil facing that acts as a vapor barrier. In temperate coastal areas such as zone 3 attic insulation of at least r30 up to a maximum of r60 is recommended. The thicker the better.

Input depth of existing blown in insulation in inches. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. To add to the. This calculator is to be used as an estimating tool only.

Inspecting your attic insulation. Most attics are insulated with blown in loose cellulose r 3 5 per inch blown in loose fiberglass r 2 5 per inch or fiberglass batts r 3 2 per inch. 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. It is not uncommon to see 15 to 20 of insulation in a well insulated attic.

Add the right kind of insulation. The insulation in your attic should be at least 12 thick. 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. For loose fill cellulose this translates to a total depth ranging from 8 inches.

Divide the desired r value by the r value per inch stated on the label. The recommended level for most attics is to insulate to r 38 or about 10 to 14 inches depending on insulation type. 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. You d need a thickness of.

Cellulose is recycled newsprint treated with a fire retardant. When adding additional insulation you do not have to use the same type of insulation that currently exists in your attic. Fiberglass is just that thin fibers of glass that trap air. Click the button to calculate the approximate r value for this job.