Q: I have a shed 5.5 x 5.6 that I’m looking to have insulated. Is there a difference in price for inter/ exterior roof insulation? also, which methods provides the best insulation from heat? I will have animals inside the shed and need as much insulation from heat as possible.
A: There are quite a few factors to consider in determining whether an internal or external application will be more cost effective. In general, it is more cost effective to install the spray foam insulation direct to the underside of the roof. This eliminates the need for additional UV protective coatings that would be required if the sprayfoam was applied ontop of the roof. You then have to consider the interior access conditions and the amount of masking (if required) to existing equipment/surfaces inside the spray area. Both methods would provide very similar results in terms of the effectiveness of the insulation. The external application would technically provide a slightly better result by the fact that the heat is hitting a painted foam surface as opposed to a metal roof but this is normally offset by the reduced cost of an internal application which can be applied slightly thicker to offset the difference.