Thermal bridging occurs when which of the following creates low-resistance paths through insulation?

• A. Air leaks in the wall
• B. Wood or metal studs in the wall assembly
• C. Sealant joints
• D. Thermal mass materials

Answer: (B)

Thermal bridging happens when a material with high thermal conductivity cuts straight through the insulation, creating a shortcut for heat flow. In a wall, wood or metal studs run from inside to outside and are much more conductive than the surrounding insulation. Because the studs provide a direct, low-resistance path, heat (or cold) moves through them easily, bypassing much of the insulating material. This reduces the wall’s effective resistance to heat transfer and lowers overall energy performance.

Air leaks involve moving air carrying heat, which is a different mechanism than conduction through solid members. Sealant joints help limit those leaks, not create the conductive path. Thermal mass materials store and release heat but aren’t about providing a low-resistance path through insulation.