Two pound medium density closed cell spray foam has the highest long term r-value of any residential insulation in Canada. It works on many other principals besides r-value. Not only does it stop drafts it has no convection currents inside the insulation itself to transfer heat from the warm side to the cold side. As well heat transfer is reduced due to the fact that the gas in the foam's cells and the foam plastic itself both have low conductivity. The foam can easily be fireproofed with a spray applied cementitious thermal barrier if half inch drywall is not an option. Perfect for new construction or old attics and cellars. It can be used as insulation, and air barrier, a vapour barrier,a drainage plane and it also enhances the structural integrity of buildings. In older homes it is especially useful in suppressing odours moisture and pests.
We use Walltite Eco and Monokote Z-3306.