External Wall Insulation: Everything You Need To Know

External Wall Insulation (EWI) systems are suitable for both new and old houses, and help significantly save money as well as greatly improve the thermal comfort of your home and protects the environment by reducing the heating energy requirements. However, only correct application guarantees optimum results!

As we know, heat moves from warmer to colder areas. Therefore, on cold days, heat from inside the building seeks to get outside. On warmer days, the opposite occurs. The heat from outside seeks to get inside. Insulating the external walls prevents heat from transferring through the walls thereby significantly optimizing the energy consumption of the building.

In order to understand how external insulation works, we can compare it with a blanket for your home, keeping the heat inside. External wall insulation works the same way since it is one continuous layer of insulation that has wrapped the whole house. EWI reflects the interior temperature back inside, keeping the room warm or cold.

Is external wall insulation an option worth pursuing?

External wall insulation is expensive but effective. Indeed, the initial cost of installing external wall insulation is high, but the benefits are instantly noticeable. It is one of the quickest energy-payback projects you can do, resulting in lower heating and cooling bills. You’ll save from 10% to 50% on heating and cooling bills, depending on where you live, what type of heating system you have, and how much insulation you add.  It is easy to apply external insulation, creating robust structures that are warm, dry and healthy, the benefits are numerous. Some types of external insulation (for example Mineral wool) improve weather proofing and sound resistance of the building. Also, EWI works as a barrier which protects the external walls of your home against the influences of weather, expanding their lifespan.

How does external wall insulation work?

External Wall Insulation (EWI) is accomplished by directly applying insulation panels on the external walls of the building before finishing (and covering it) with a rendering system for impact and weather protection. Both solid walls and cavity walls can be insulated externally.

External insulation can be anchored to walls using mechanical fixings (often with plastic heads, as metal conducts heat) or mortar dabs, or a combination of both. Depending on the type of external insulation used, changes to the original wall finishes – as in the case of pebble dash – are sometimes needed to ensure a smooth application.

Once the external insulation board is applied, finishes are available to create and replicate all sorts of looks, including dash and brick. Those seeking a brick finish have a number of options: renders designed to create an authentic brick effect, synthetic brick slips, or slips cut from real brick.