Special consideration was given in the selection of which Spray Foam Insulation to use as not all Spray Foams are alike. Icynene provides two types of spray foam, a water based propelled open cell and a chemical based propelled closed cell. The propellant used impacted our canary differently. One was tolerable, the other not. Though the closed cell has a higher R factor per inch, the open cell formulation is free of VOC’s because of the water based propellant. There is some gassing off or ‘fishy smell’ immediately after the application of the open cell formula, which cures within 24-hours. Canaries should wait 1-2 days before entering a well-ventilated house.
Because of the lower R factor of the open cell spray foam, it was necessary to increase the typical roof rafter 8” to 16” to have the required depth for the extra foam needed in order to meet the required R value for the Maine climate.
Other alternatives canaries may wish to investigate are sheep’s wool and aerogel. However due to our canary’s allergy to wool, this option wasn’t possible. Aerogel was prohibitive due to its cost.
As an aside, one of the benefits of using the ICF block system for the exterior walls meant no additional insulation was needed on the main floor. For the Maine climate and to provide a cross system for the exterior finish to connect to, we did opt to put one extra layer on the outside of the building. This was ultimately the best solution for our canary as there is no direct daily interaction with the spray foam used in the attic even though great care was taken to find one she could tolerate.