What is External Wall Insulation?

External wall insulation, or E.W.I., is a layered insulation system that is fitted like a jacket over the outside of a building. Its main advantages are that it thermally protects the whole home as well as protecting the structure of the building.

External wall insulation can be fitted with minimal disruption to daily life as all the work is done outside, and it dramatically prolongs the life of the structure it is applied to. It is most effectively used on hard-to-treat buildings like park homes.

How it works

Now you know what external wall insulation is, you may be wondering how it works. Imagine our cladding system being like a big jacket; we wear jackets in the winter to prevent our body heat from escaping, therefore keeping us warm. In the same way, your home’s Therm-eco jacket will keep the warmth you generate within your home from being lost through the walls. 

During the summer we don’t wear our thick jackets so that our body heat can escape and keep us cool. But a park home is just as vulnerable to the heat coming in as it is going out, so having protection from heat penetration is equally important in the warmer months. With the lowest u-values available, your Therm-eco external wall insulation system is proven to be the most efficient way of doing both these jobs.

Now imagine having a jacket that not only provides thermal protection, but also reduces noise intrusion, stops damp and mould, prevents degradation, and comes in a range of colours to suit any taste. A jacket so hard-wearing that you don’t have to replace it for a guaranteed minimum of 10 years. That’s what external wall insulation is.


For even more information on external wall insultation, you can read our blog.

How It’s fitted

Stage One

The first part of the job is preparing the home for the system to be fitted. All fixings that protrude from the surface need to be removed, i.e. exterior lights, aerials, etc. Once this has been done, the starter rail is fixed to the bottom of the wall to support the insulation, and sill boards fitted to the bottoms of the windows to compensate for the depth of the cladding. 60mm thick insulation board is then fixed to the outside of the whole home and all the exposed edges are fitted with corner bead.

Stage Two

A special polymer-based render designed specifically to adhere to our insulation board is now applied to the whole home, and a glass fibre mesh is set into the surface to give it maximum strength. This is finished off with another thinner layer of render to cover the mesh and prepare for the final stage.

Stage Three

The final stage is to render on a top coat in your choice of colour. The render contains high quantities of marble dust which, because it is one of the hardest stones available, significantly increases the durability of the visible surface, as well as providing an attractive texture. This layered, integrated system of insulation provides a decorative and maintenance-free finish which we proudly guarantee for ten years.

The facts

Government research has proven that external wall insulation (E.W.I.) has several major advantages over the alternatives: 

  • The thermal values of E.W.I. are consistently much higher than with cavity wall or internal lining insulation. 
  • Because E.W.I. is applied to the outside of your home, it protects the structure of the building where other systems do not.  
  • Because E.W.I. work takes place entirely outside, it can be fitted with almost no interruption to your daily life.  
  • One of the biggest advantages of E.W.I. is that it can be used to improve the appearance of your home and, with a Therm-eco E.W.I. system, you can choose from a huge range of colours to suit your taste.

All the major benefits of having an external wall insulation system like ours fitted to your home can be found in the government’s best practice guide on external insulation.



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