Do I need solid wall insulation?
Did you know that solid walls let out twice as much heat as cavity walls. It therefore makes a great deal of sense to insulate them. It is possible to insulate either the inside or outside of your solid wall and each option has its pros and cons.
If your home was constructed before 1920 then there is a high change it was built with solid external walls rather than cavity backed walls. For homes that were made of bricks you can also tell how your home was constructed by checking the thickness of your external walls. You can check the thickness of the homes bricks by measuring them through an external doorway or window. If a wall is less than 10 inches thick, it is probably solid. Stone built houses can, in some cases, have much thicker walls. In most cases these are very rarely cavity walls.