External Wall Insulation, or EWI, is the application of insulating boards onto the external walls of the house. The house is then finished with high quality render. We offer a number of options to make your home look really unique – from your choice of colour, to brick-effect, pebble-dash, and other speciality finishes.
External Wall Insulation is particularly suited to rendered or painted properties, as it can be installed and covered with rendering. However, homes with exposed bricks can also be insulated externally as a simulated brick face can be used to cover the insulation.

How Is External Wall Insulation Installed?

Firstly, if the property has existing render, a render test must be carried out to see if it is strong enough to hold the insulation. If not, all the existing render will need to be removed before attaching the insulation to the brickwork.


If the render test shows that the existing render is firmly held in place, the render can be smoothed. This will then be ready for the External Wall Insulation to be applied directly on to it.

Removing pipework from the outside of the building is another important step before installing any External Wall Insulation. These will be reinstalled at the end of the process (and may be extended in some instances).


Perks of EWI

  • Transform the appearance of your home

  • Increasing the monetary value of your home by an estimated £16,000 - £20,000

  • Solving problems with your existing render

  • Low maintenance system

  • Offers total weather protection; virtually eliminates condensation and removes the chilly, damp atmosphere

  • Warmer house in winter and cooler house in summer

  • No disruption inside your home and no reduction in internal floor area

If you are interested, please don't hesitate and CONTACT US now to arrange a free consultation with a member of our team of experts.

Different types of Insulation

There are a number of different types of insulation that can be used for External Wall Insulation. Not all materials perform the same. For example, numerous other installers will offer expanded polystyrene boards to insulate your walls but they do not perform as well as other materials at insulating your home. 

Our Top Choice - Kingspan Phenolic Foam

Kingspan Phenolic Foam has excellent thermal performance comparatively to other products.

Phenolic foam also offers exceptional high vapour permeability, helping reduce condensation and prevent mould from forming.

Using a material with high degree of vapour permeability ensures your house can breathe.

The key factors you need to take into account for each type of insulation are:


  • Fire rating

  • Thermal performance (how well it insulates relative to its thickness)

  • Durability

  • Biodegradability and environmental impact

  • Moisture resistance

  • The breath-ability or vapour permeability (particularly for solid walls)

Considerations with EWI

  • It can be difficult to get planning permission in a Conservation Area

  • Brick houses will need a simulated brick facing if rendering is not appropriate

  • It needs a specialist to design the system and install it properly - we can assist you with this

  • It must be correctly fixed so that it does not bridge the Damp Proof Course or crack 

  • Rising damp must be rectified before fixing the insulation so that damp is not trapped inside