What is the primary function of insulation in a masonry cavity wall and where is it placed?

• A. It reduces thermal bridging and increases R-value; placed in the wall cavity between the inner wythe and veneer.
• B. It provides structural support; placed as exterior layer.
• C. It improves sound attenuation; placed in the outer veneer.
• D. It prevents moisture; placed behind veneer.

Answer: (A)

Insulation in a masonry cavity wall is focused on slowing heat transfer to boost the wall’s resistance to heat flow (R-value). In a cavity wall, it is placed in the hollow space between the inner wythe (the structural masonry) and the exterior veneer. This location minimizes thermal bridging caused by the solid masonry and wall ties, helping keep interior temperatures more stable and reducing energy loss. Insulation can take the form of batts, boards, or spray foam that fills the cavity, rather than being placed as an exterior layer or behind the veneer.