SHOULD I I NSULATE I T?
EXTERIOR WALLS: YES
While it is possible to insulate inside brick walls if they have a cavity, in-wall insulation is even more important if you have a steelframe prefab house with hollow walls. Fibreglass insulation should be installed
The best time is when the roof is being built, naturally, and it’s legally required in SA, so most houses will have insulation there. Spray-foam or spray-in cellulose fibres can easily be added later, if necessary. (