The Ultimate Envelope – Honest, Effective AND Affordable
Thermal bridging is a term that we've been hearing more and more of over the years. However it is very rare that all the thermal bridges are accounted for when designing building envelopes and calculating the R-value for various assemblies. Recent studies have shown that even a very small percentage of uninsulated surface area can drastically decrease the overall R-value of a wall, roof or floor.
Air barrier is another buzz word that has become more popular over the past decade. The newer multicomponent rubber and bituminous based systems have come a long way since their polyethylene predecessors. Now we have all sorts of lab tested performance data to compare products against each other and provide the basis for specification and code requirements. But are we actually achieving these leakage rates when installed in the field? How many projects are actually testing their wall assemblies on site, how many have the budget to do so?
Our experience with air barriers has been mostly with high-rise multifamily affordable housing, so budgets were tight. These buildings were shooting for a high performance certification where a continuous unbroken air barrier was a requirement, but it was up to the energy consult to define what this actually meant for each project.
This paper looks at these issues in more detail, providing first hand accounts of real problems and potential solutions found in the field.