Thermal bridging occurs when a material with higher thermal conductivity, like wood or steel framing, creates a pathway for heat to transfer more readily than through the surrounding insulation, effectively weakening that section’s overall insulating performance compared to the insulated cavity areas around it.
Wood studs, while less conductive than steel, still transfer heat considerably faster than the insulation typically installed between them, meaning even standard wood-framed walls have thermal bridges at every stud location throughout the structure.
Steel framing creates even more pronounced thermal bridging than wood, since steel conducts heat dramatically faster, making thermal break strategies particularly important in steel-framed construction to avoid significant energy performance penalties.
What Causes Thermal Bridging?
- Wood or steel studs within an insulated wall cavity
- Structural connections penetrating through insulation layers
- Window and door framing interrupting wall insulation
- Uninsulated structural elements like balconies or parapets
Why Is Thermal Bridging Important?
Because thermal bridges create localized weak points in an otherwise insulated envelope, their cumulative effect across an entire building can meaningfully reduce overall energy performance compared to what the insulation’s rated R-value alone might suggest, a gap between theoretical and actual performance that building science increasingly emphasizes addressing. This recognition has driven growing adoption of exterior continuous insulation specifically to counteract this effect.
Thermal bridges also sometimes create visible symptoms, like slightly cooler wall surfaces at stud locations that can occasionally show as faint patterns on interior finishes during extreme weather, or increased condensation risk at these localized cooler points compared to the insulated cavity areas between them. Recognizing these patterns can help homeowners understand otherwise puzzling comfort or condensation issues.
Thermal Bridging vs. Thermal Bypass
Thermal bridging involves heat loss through direct conduction within a solid material. Thermal bypass involves heat loss through actual air movement past or around insulation, two distinct mechanisms both requiring different solutions to address effectively.