In colder climates we are used to thinking about designing the building enclosure as a series of critical "barriers"; air barrier, vapour barrier, moisture barrier, convective barrier, and thermal barrier. We also think that each of these control layers is thin and performs most of the intended function in the closure assembly. Our codes and standards were drafted by people with these assumptions and mental construct.
What happens when you use a material that provides a number of the control functions but the material is thick and the properties are provided through the thickness? What if the material was combustible and maybe off-gassed or shrank when heated? Foamed plastic insulations are such a material. Some code reviewers and some building enclosure professionals have trouble understanding the building science implications of using foamed plastic insulations and are, therefore, uncomfortable with them. This presentation will address how material properties of foamed plastic insulation impact enclosure performance and code acceptance.