Reinforced Concrete Wall U Value

Table 3 shows the approximate percentage of grouted and ungrouted wall area for different vertical and horizontal grout spacings which can be used to.

Reinforced concrete wall u value.

For concrete the k value depends on its bulk density and the moisture content in service. U value has an inverse relationship to r value. For example a building with material with an r value of r 11 converts to an u value of 0 09 1 r or 1 11 0 09. The u value is the measure of heat transmittance through a material and the lower the u value the less heat is transmitted through a construction i e.

Calculating the inverse of that 1 r would give you a u factor in the range of 1 67 to 0 83. For instance if you have a material with an r value of 12 attached to another material with an r value of 3 then both materials combined have an r value of 15. For a 6 inch slab r value would be between 0 6 and 1 2. Table 2 lists calculated u factors and r values of various thicknesses of concrete masonry walls for concrete densities of 85 to 135 lb ft 1 362 to 2 163 kg m with various core fills.

From table a4 there is a u correction of 0 01 w m2k which applies to both the following cases. Determine the thickness of the insulation layer required to achieve a u value of 0 21 w m2k if insulation is between the joists and 0 26 w m2k if insulation is between the rafters. Reinforced concrete walls resist the compression and tensile forces produced by an earthquake. As we said before the r value measures the thermal resistance of a material.

A reasonable r value for a normal concrete slab can be estimated using an r value the thermal resistance per inch of thickness between 0 1 and 0 2 and multiplying it times the slab thickness. The better the insulation quality.