Foam must be covered
It is important (and required in most cases) to cover exposed foamed plastic insulation, be it site-applied, or purchased in sheets. This is because foam is extremely combustible, and if left uncovered presents a fire risk.
That’s why the National Building Code mandates that exposed foam in most building areas has to be covered. It’s one of the things our inspectors will check homes for during a final inspection.
Don’t get the wrong impression: foam, whether it’s site-applied or comes in pre-manufactured panels, is amazing stuff, and nothing else out there offers the same bang-for-the-buck in terms of insulation value. To put things in perspective, site-applied two-pound foam offers R6 per inch, compared to Fibreglass batts, which offer R3 per inch.
In addition to being a spectacular insulator, foam is also impervious to water and air, so it can’t trap moisture. Site applied foam also serves to seal homes from air leakage, which just bolsters its insulative properties and also means that in most cases, a vapour barrier (plastic) isn’t necessary.
Exposed foam can be covered in a number of ways, including the construction of a stud wall closed off with drywall, application of a stucco coat, or the use of specialized paint-like products intended for that purpose.
Foam may be left unexposed in crawl spaces, that is, areas under finished floors that are less than 1.8 metres in height.
If in doubt, call one of our inspectors for clarification.