Most houses in the greater Dublin area and much of Leinster are built with a single leaf of blockwork, brickwork or concrete. Most older houses have no insulation in these walls and the heat goes straight through the wall fairly quickly, usually in about 30 minutes in the winter. Newer houses may have some small amount of insulation on the inside of the wall in the form of 65 mm of fibreglass between battens covered with plasterboard. The insulation is never fitted between the floor joists, as it should be, in this 250mm deep band around the perimeter of the whole house so the heat losses are significant. Often the central heating pipes are run behind the plasterboard and the hot pipes touch the cold blockwork and lose much of their heat before the hot water gets to the radiator. This is why most houses have such unnecessarily large and increasingly expensive heating bills and low levels of comfort.

There is only one effective way to upgrade the insulation in these walls to overcome these problems and that is with an external insulation system. External insulation completely wraps the cold solid walls with a continuous layer of insulation like a thick cosy warm blanket. If installed correctly all problems of ‘cold bridging’ at floors, lintols and the eaves are eliminated. The impact is felt before the installation is completed and the warmth and comfort are usually felt as a huge relief and increase in the standard of living. People are not used to such comfortable living conditions and often comment they would have done it years ago if they had understood the benefits. 

With the insulation on the outside the masonry walls then absorb and store the heat from the inside. This reduces the fluctuations in temperature that are felt when doors and windows are opened momentarily and from draughts if the house is not airtight. The heating system can function more efficiently and a significant reduction in heating costs will show up on your next bill.

One word of caution: walls built with hollow blocks, sometimes called ‘cavity blocks’, can not be injected with insulation of any type in a way which will improve the insulating performance of the wall. Anyone trying to sell you this type of solution is should be avoided.