Masonry

A masonry wall is a particularly poor thermal barrier. A typical masonry cavity wall (4-in face brick on the exterior, an air space,

4- in concrete block, an air space, and a layer of gypsum wall board) has a thermal resistance equal to approximately 1 in of rigid insula­tion. Exterior opaque masonry walls should have maximum U — value of 0.11, requiring insulation rated at R-7 or greater. This can be accomplished in the following ways:

1. Place a layer of preformed rigid insulation between the exte­rior face brick (or other finishing material) and the concrete block during construction (Figure 3-13). Another method is to leave the space empty and then fill it with a foam insulation before capping the wall.

2. If no air space exists between the exterior face brick or other exterior finish and the concrete block, it will be necessary to add a layer of suitable insulating material (rated R-7 or bet­ter) on the inside surface of the block (Figure 3-14). The insu­lating material can be rigid insulation attached to furring strips or preformed rigid insulation secured in place with adhesives. An interior wall finish is then applied over the insu­lating material.

If the wall is constructed entirely of concrete, apply preformed rigid insulation to either side by adhesive bonding and cover the layer of insulation with a wall-finish material (Figure 3-15). The insulation must be rated R-7 or better.

Posted in Audel HVAC Fundamentals Volume 1 Heating Systems, Furnaces, and Boilers