The value of continuous insulation is a source of contention among some building design and construction professionals. Increasingly stringent energy code requirements are calling for minimal amounts of continuous insulation that some claim are prohibitively expensive, structurally complicated, or marginally impactful versus increased cavity insulation.
Professionals are generally aware of the potential for thermal bridging in construction assemblies – the phenomenon by which heat conducts more readily through structural/support members relative to the adjacent cavity insulation, thus reducing the effective performance of the overall thermal barrier. Yet, few professionals understand the effective impact structural framing has on the rated R-value of a cavity insulation product.
Seeing impressions of studs in a wall system during an infrared scan is one thing, but how much of a difference does thermal bridging actually make?
…Well, if your assembly utilizes steel studs, the answer is: A LOT.
The following table presents the effective insulation/framing layer R-values for both steel and wood stud wall framing.