Q. I have heard that spray foam can insulate better with a lower r-value installed, If so why is this???
A. Yes this is true. Its because of how well it seals and carries the r - value through the entire wall or ceiling. If spray foam has an r – value of 7 per inch, it is the actual effective value. Conventional methods are friction fit leaving room for air movement around your insulation. Traditional vapour barrier can be severely compromised by screw and nail penetrations which can lower the benefits of an air seal.
Q. I have a new house just done with batt insulation and 6 millimeter poly vapour barrier. How much will I save on energy cost with spray foam??
A. You could expect as much as 40% drop in your energy bills and that is if your insulation was done 100% perfectly. Usually batt insulation is not installed correctly as pipes and wires run threw walls and are very hard to seal to and insulate around. Spray foam will expand and fill every nook and cranny of your wall and those hard to reach places, giving you a true seal and a very well insulated building.