Energy Performance Certificates Belfast: Impact of Cavity Wall Insulation


Epc4less is a company that provides Energy Performance Certificates, also known as EPCs, in Belfast, Northern Ireland. This article epc4less make some recommendations on how to increase the energy performance of your house by insulating its external wall.

You can find more information if you contact directly epc4less. Or, check out Energy Performance Certificates, Belfast.

Introduction: What is a cavity wall?

Before the 1920s, houses in Belfast, Northern Ireland were built on the basis of solid stone or solid brick walls. However, after the 1920s and especially in the time period after the 1930s, this began to change and cavity wall was introduced. A cavity wall consists of two walls: the inner wall and an outer wall. The inner wall is also known as the masonry wall or the inner block leaf. The outer wall is also known as the face brick or the outer brick leaf. In between the two walls there’s a cavity that’s filled with air.

Houses built after the 1980s

After the late 1980s, Building Control standards in Belfast required houses to be built with cavity insulation. Cavity wall insulation options range from mineral fiber wool or polystyrene granules (also known as beads) to polyurethane foam or Kingspan foam blocks. 

Houses built between 1930 and 1980

In the time period before the 1980s, houses that were built in Belfast, Northern Ireland, didn’t have cavity wall insulation as they were built. Building Control standards at the time did not require this. 

However, if you want to insulate the cavity of your house you need to hire a specialist to do it. They will inject insulation in the walls of your house by drilling little holes on the wall around the perimeter of your house. Then, they will create a solution based on polyester beads and a water-based adhesive and will inject this in the cavity. They will fill the holes with a cement mix or any other type of material that comes closest to matching the existing exterior of your house.


Energy Performance Certificate (EPC) rating

All in all, insulating the cavity of the external walls of your house can greatly improve the energy performance rating of your house. When you take a look at the overall heat energy of your home, you will find that up to 35% of that heat energy can be lost through the external walls of your house. By insulating the cavity of your walls, you can improve your Energy Performance Certificate rating by about 5 to 10 points. However, the EPC rating impact will depend on the size of your house. The bigger your house, the longer the perimeter of the surrounding wall will be. Thus, the bigger your house, the more impact cavity insulation will have on the EPC rating.

If you own a mid-terrace house with other dwellings either side, cavity insulation will only have a small impact on the EPC rating of your house. If you own a detached house cavity insulation will have a greater impact on the energy performance.

EPCs remain valid in a register in Northern Ireland for 10 years.


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