R Value Of Concrete Wall Below Grade

By doubling the thickness of the wall to 16 inches the r value only increases by 0 50.

R value of concrete wall below grade.

These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. In addition the doe recommends r 10 to r 20 insulation for under a slab which we have not taken into consideration for this article. 564 to obtain copies of this reference. R value is a measure of insulation s ability to resist heat traveling through it.

Concrete and block walls. 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. Ensure minimal long term moisture absorption.

The r value of an uninsulated 8 inch thick basement wall built using normal weight concrete is 1 35 based on data from the 1993 american society of heating refrigeration and air conditioning engineers handbook. The r value listed by pca for a normal weight 144 pcf 6 inch concrete wall is 1 23 and includes inside and outside air film resistances which contribute to overall thermal resistance. For example if you have a type of insulation. Other engineering sources cite the r value of earth as about r 0 25 per inch or double our calculation.

Concrete block wall with perlite in cavities r 2 9. R 0 125 per inch for soil sounds pretty reasonable if we assume about 20 moisture content and if we consider for comparison or a sanity check that the r value of uninsulated concrete is about r 0 8 inch. Find your zone on the map and then use the above insulation r value chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces. Concrete block wall with air in cavities r 2 0.

By comparison most xps warranties typically cover only up to 90 percent of the published r value to account for the r value degradation that occurs in the field. The minimum insulation r value recommended by the department of energy for horizontal below grade surfaces in cold climates is r 10 to r 15. In addition to r value stability rigid foam insulations differ in their rates of moisture absorption and their ability to dry.