Useable Space Attic Insulation Thickness

Having the correct amount of attic insulation can help you maintain a comfortable temperature throughout your home and help save money on your energy bills plus prevent major issues like ice dams in the winter.

Useable space attic insulation thickness.

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. Standard joist spacing for the installation of attic flooring materials is 16 inches on center oc meaning the distance from the center of one joist to the center of the next joist is 16 inches. R 38 is the industry standard and the minimum thickness for r 38 is 12 inches.

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. R value is a measure of insulation s ability to resist heat traveling through it. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. 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.

Some types of thicker foam board insulation are available but they may need to be special ordered. It comes in standard size 4 8 sheets and smaller sizes in many different thicknesses from 1 4 inch to 2 inches. They come with or without a paper or foil facing that acts as a vapor barrier. 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.

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. You d need a thickness of. Measure the area needing insulation. Insulation level are specified by r value.

If you think you re among the 90 of us homes that are under insulated 1 performing a simple insulation inspection will help you determine your insulation needs. The table below shows what levels of insulation are cost effective for different climates and locations in the home. The higher the r value the better the thermal performance of the insulation.