Thermal Bridging Research: Roof to Wall Transitions

One of our many in-house research efforts is a large, collaborative project. We investigated the Thermal Performance of Façades through the AIA Upjohn Research Initiative.

Thermal bridging in building construction occurs when thermally conductive materials penetrate through the insulation creating areas of significantly reduced resistance to heat transfer. These thermal bridges are most often caused by structural elements that are used to transfer loads from the building envelope back to the building superstructure. Though design professionals generally understand that thermal bridging is a concern, few can quantify the extent of its impact on building performance.

Small changes in designs can still lead to dramatic improvements in performance. With careful detailing and attention to the issues of thermal bridging, the design and construction industry can improve the performance of our building envelopes.

Today we’re sharing our findings regarding roof to wall transitions.

 
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Transitions from roofing systems to wall systems, which occur when building massing steps back at upper floors, pose similar challenges to transitions between wall systems. We found the continuity of the thermal barrier was often compromised in typical detailing due to flashing, blocking, and structural supports. In the infrared images taken, many were noted to have a 40-75% decrease in the R-value in areas where this transition occurred. Some of these installations demonstrated that more aggressive detailing readily addressed the problem. Because gravity assists in the performance of these systems (unlike soffits) the structural complexities associated with changes in direction can be mitigated easily. With careful attention, we can minimize blocking and control fastener placement and select non-conductive flashing materials that will minimize thermal bridges.

Related:
Thermal Performance of Facades: Final Report
Thermal Bridging Research: Curtain Walls
Thermal Bridging Research: Investigating Insulation Thickness for Renovations
Thermal Bridging Research: Masonry Veneer Walls
Thermal Bridging Research: Window Transitions
Thermal Bridging Research: Foundation to Wall Transitions
Thermal Bridging Research: Rainscreens
Thermal Bridging Research: Metal Panel Wall Systems
Thermal Bridging Research: Parapets
Thermal Bridging Research: Transitions between Wall Systems
Thermal Bridging Research: Soffits