What Is the Insulation Quality of Exterior Brick Walls of Buildings?

Brick Wall Characteristics

• Many brick exteriors are not actually brick walls, so the insulation value of a brick finish will depend on whether or not the visible outer layer of brick wall assemblies are a standard brick, a thinner brick veneer or perhaps a simulated brick. When a building does have brick walls, the bricks may or may not have interior cavities. In turn, builders may or may not fill brick cavities with insulating materials during construction. Most exterior walls include an array of additional materials, such as insulating panels and wraps, as well as air space between some layers that augment insulation quality.

Insulation Value Basics

• Two common measures of insulation quality are R-value and U-value. R-value is a measure of resistance to heat transfer, where higher numbers signify better resistance. U-value is a measure of heat transmission, where lower numbers signify less transmission. The higher the R-value or lower the U-value, the better the insulation quality. The R-value of a 3 5/8-inch brick is 0.44 and its U-value may be as high as 2.3, so a brick wall by itself has relatively poor insulation quality.

Brick Wall Assemblies

• Recommended R-values for well-insulated wall assemblies are between R-20 and R-30, according to the University of Iowa Extension. Jason Yana for the Masonry Advisory provides examples of how combining a brick veneer with other insulating materials produces a wall section with R-values over R-20. Similarly, the U-value of brick wall configurations can range as low as 0.3 for modern wall assemblies that include other insulating construction materials.

Considerations

• Other aspects of brick wall construction can affect brick insulation quality. The soundness of the mortaring and the seals around windows and doors installed in the walls are examples. Caulking these areas and between changes from brick to other siding materials can improve insulation value. It is important to use the appropriate caulking material to make sure the caulk adheres to the surfaces. For brick, silicone and urethane/ polyurethane will create seals with other construction materials, advise University of Nebraska-Lincoln Extension specialists.