Some types of stone and masonry walls—and less frequently, wood—are essentially solid all the way through. Unfortunately, solid-walls are less efficient at blocking heat flow and are generally more difficult insulate than walls with cavities. However, if you are willing to make some changes to the appearance of your house, it is possible to drastically improve the energy efficiency of your solid-wall home through wall insulation.
Because there is no gap to fill with insulating materials, solid wall insulation necessarily alters either the inner or outer appearance of your house. If you choose interior insulation you’re going to have to give up some of your living space – interior insulation is between 1 -4 inches thick and should be applied to all walls that boarder the outdoors. Alternatively, you can choose exterior insulation, which adds about 1-4 inches of thickness to the exterior face of your walls. You can choose to clad or render the new exterior walls in a similar way to the original walls, or go for a completely new look. Existing homes taking this approach can be made more efficient than even most newly constructed homes!
Insulating solid walls, either from the inside or outside, is a major undertaking and not recommended for even very competent do-it-yourself handy-persons. If you are thinking of adding wall insulation to your solid-wall home we recommend consulting a specialist first and, if possible, conducting this work as part of a larger renovation scheme in order to increase the cost/benefit ratio.
If you are considering solid-wall insulation purely for energy efficiency reasons we recommend getting a home energy assessment to identify whether or not it is the most cost effective way to lower your energy bills and meet you comfort and savings goals.