October 20 2009

Thermablok Insulation Strips - Another Tool in the Arsenal Against Thermal Bridging


Now that the Solar Decathlon 2009 is over I have time to pour over the tremendous number of novel materials, products, equipment the teams chose to install. One of the many, this one used by Team California, is a product used to prevent thermal bridging at wood and steel framing members called Thermablok. The website describes the material as "a flexible aerogel and fiber composite insulation with the lowest thermal conductivity of any building insulation product on the market." (The site claims a U-value of 0.0078). A bold claim perhaps in an industry that is clamoring to find more and more efficient building insulations, but a claim worthy of investigation.

By simply adding one strip to each stud edge before drywall, Thermablok interrups the thermal bridging process through the studs.

Correctly installed ThermablokThe intended use is straightforward. The Thermablok insulation strips are applied using peel and stick backing to the face of the studs or framing, thereby breaking direct contact between the stud and whatever sheathing or finish material is being applied on top. Fasteners must still be used and do penetrate the Thermablok strips, but losses through those elements could be negligible depending on the type and spacing.

The skeptic in me is cautious about claims that one product alone can make a building significantly more efficient. I praise Thermablok for creating a good product and really addressing a critical flaw in the construction process used in buildings today. At the same time it is evident that a single change to traditional building methods does not create the type of buildings we need to execute to bring us into the next century. Does Thermablok has a place in the solution?  Absolutely. Continued emphasis however needs to be placed on reduced design for thermal bridging, air tightness, efficient HVAC systems, reduced plug loads, better glazing technologies, and much more. We as designers, builders, consumers and policy makers need to use all the available tools in our arsenal to find lasting solutions.

For more information on Thermablok visit the product website. You may also want to take a look at the 2009 Team California Solar Decathlon project to see how the use of Thermablok affects design.

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