Infrared images of structural thermal bridging


    As architects increase the insulation and tightness of building envelopes, the contribution to heating and cooling energy loss of the structural elements present in the envelope increases. Here are some images to illustrate – if not quantify – some of the common conditions that the structural engineer can improve upon.

    The Structural Engineering Institute (SEI) Thermal Bridging Task Committee is developing information on this topic, and compiling ways to detail structural elements that intersect building envelopes to minimize this energy loss. They expect to have a document developed by the end of 2012.

    Image 1 – Heat loss occurs at each steel roof joist end through the brick façade, along with soffit heat loss and roof edge convective losses   Image 2 – Steel roof trusses conduct heat through the loose attic insulation and allow heat to escape into the attic.
    Images 3 and 4 – Steel beams and open-web steel joists that penetrate the insulated exterior wall conduct cold temperatures to the interior. Such point sources of thermal bridging may not represent much energy loss, but they can allow condensation of cold surfaces, which can lead to other types of problems.
    Image 5 – Steel angle lintels above windows conduct heat out of warm residential units on a cold night.   Image 6 – Thick steel shelf angles at each floor of building with brick façade represent heat loss along continuous lines.
    Image 7 – Cold-formed steel studs of skylight sidewall above roof conduct winter cold temperatures inside.   Image 8 – From the exterior, cold-formed steel studs and stud tracks conduct heat to the exterior.
    Images 9 and 10 – Undulating concrete cantilever balconies in a residential tower create continuous thermal bridging at each floor level.
    Image 11 – Uninsulated concrete basement walls are warm in wintertime.   Image 12 – Foundation top edges are common areas of significant losses

    James A. D’Aloisio is an Infraspection Institute-trained thermographer, and a principal with Klepper, Hahn & Hyatt, East Syracuse, N.Y. He is a member of the SEI’s Sustainability Committee, and Chair of the SEI’s Thermal Bridging Task Committee.