R Value Of Concrete Wall Below Grade

The reason that it is important to make a good estimate for the current r value for uninsulated spaces is that small changes in r values result in large changes in heat loss when the total r value is low.

R value of concrete wall below grade. 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. 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. And sheath it with 1 3cm sheets of thermax and 1 3cm sheetrock the total r value would be 14 75. By doubling the thickness of the wall to 16 inches the r value only increases by 0 50.

Depending on the density of the blocks an 8 inch thick block wall without any other type of. 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. Ensure minimal long term moisture absorption. Concrete block makes a cost effective and structurally sound wall but it has little thermal resistance.

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. Call pca at 847 966 6200 ext. Concrete block wall with perlite in cavities r 2 9. If you are building your house you have the advantage of being able to insulate properly right from the.

Other engineering sources cite the r value of earth as about r 0 25 per inch or double our calculation. In addition to r value stability rigid foam insulations differ in their rates of moisture absorption and their ability to dry.