Wall insulation
Cavity wall
If your home was built after the 1930s, the chances are that its external walls are made of two ‘skins’ with a small gap between them. This means they are ‘cavity walls’ and the gap between them can be filled with insulating material to stop the warmth escaping to the outside.The cavity can be insulated by drilling a series of small holes into the mortar at regular intervals and injecting the insulation material into the cavity. The holes are then refilled. There are two types of cavity wall insulation material available through Energy at Home; mineral wool fiber, or polystyrene beads. The mineral wool fiber has been used effectively for many years, however the polystyrene beads are more efficient at keeping the heat in, and are water repellent.
External solid wall
If your home was built before 1930 it will most likely have solid external walls with no cavity. Up to 45% of the heat from your home can escape through the walls if they are not insulated.
External solid wall insulation works by adding a thermal layer of material to the exterior walls. The insulation slows down the rate at which heat is lost through the walls. It’s a bit like wrapping your home in a blanket to keep it warm.
Insulating these walls will keep the warmth in the house for longer and makes homes more comfortable and cheaper to heat.
If you’re not sure whether you have the right type of walls, assessors will be able to identify whether your house is built with solid or cavity walls when they visit your home to undertake an assessment.
A fact sheet about external solid wall insulation from Centre for Sustainable Energy is available here
If you decide to go ahead with having external wall insulation installed, you will need to find out whether you need planning permission or not. If you do need planning permission, this will need to be in place before any works can commence. More information about planning is available here.
Internal solid wall
Internal solid wall insulation works by adding a layer of thermal material to the inside surface of the external walls of a property with solid walls (please see above for more information on property types with solid walls).
Installing this type of insulation is usually more expensive and more disruptive than having external wall insulation applied, however, it may be particularly appropriate where you are not able to change the external appearance of the property e.g. in cases where the external character needs to be maintained.
Planning permission is not needed for internal wall insulation, however, if the property is listed, it is likely to require listed building consent. More information about planning and listed building consent can be found here.