The basic gauge of the effectiveness of any insulation is its R-value. Insulation is designed to stop the flow of heat. The more heat the insulation stops, the higher the R-value of that insulation.
When compared to fibreglass batt insulation, spray foam insulation has a higher R-value at a given thickness. In other words, 2 inches of spray foam will insulate your roof better than 2 inches of fibreglass batts.
Cellulose fill, either blown-in or applied by hand, also has a higher R-value than fibreglass batts at the same thickness. But, again, the R-value of spray foam insulation is almost twice as high as cellulose fill insulation of the same thickness.
As important as R-value is in how well insulation works, it is not the only thing to consider when choosing the best roof insulation. Moisture will cause both fibreglass batts and cellulose fill to lose R-value. Even slight moisture, that you can’t see or feel, can reduce the R-value of fibreglass batts.
Neither fibreglass batts or cellulose fill insulation can seal every gap in your roof. Heat can pass through the open gaps and this reduces the R-value of the insulation, although the R-values listed for fibreglass or cellulose do not take this into consideration. In other words, the actual R-value of installed fibreglass batt or cellulose fill roof insulation is lower than the listed R-value.
Spray foam insulation is not affected by moisture. In fact, it can stop minor leaks because, when it is applied, spray foam insulation spreads to fill every gap and seal your roof. Pollutants and other airborne irritants that might get through the gaps left by batts and fill are kept out by spray foam insulation.
Perhaps best of all, insulating your roof with spray foam insulation costs about the same as other insulations.
The spray foam roof insulation specialists at Foam Comfort have the experience you need to get the most from your insulation.