Rateavon Jersey

Insulated Facade Systems

A Guide to External Wall Insulation

What is External Wall Insulation?

External Wall Insulation (EWI) systems, by definition, are applied to the exterior of a property offering improved energy efficiency, weather protection and building aesthetics.

An EWI system consists of rigid insulation boards fixed to the exterior walls of a property creating a ‘thermal jacket’, which is then over-coated with a weather protective, breathable, hard wearing, attractive polymer modified render.


Why Choose an External Wall Insulation System?

Your property could be losing up to 45% of its heat through the walls alone (figures provided by EST). EWI systems can help reduce this significantly whilst providing numerous other benefits to the householder.

  • Lower Fuel Bills: Extremely high insulation levels can be achieved over other forms resulting in savings on energy bills. An average solid wall semi-detached home could save around £375 per year on fuel costs (figures provided by EST).
  • Condensation: EWI can eliminate interstitial and internal condensation. Associated problems such as damp internal walls and mould growth may also be overcome.
  • Prolonged Building Life: External Walls of the building are protected from the effects of the weather. Some systems have an assessed minimum life of 30 years.
  • Building Appearance: EWI systems come with an extensive range of decorative finishes and colours, from the traditional brick finish to the more modern silicone textured renders and many in between.
  • House Value: Having an EWI system installed to your home can increase the value.
  • Installation: Because EWI systems are installed externally you never have to leave the comfort of your own home during the installation and internal space is not infringed upon.
  • Warranty: EWI systems come with a 10 year materials and labour warranty.
  • Funding: Some partial funding may be available depending on property and circumstances.
  • Sound Proofing: EWI systems also offer a level of acoustic resistance, reducing the effects of traffic noise.
  • Fire Protection: Recognised EWI systems have been assessed and approved by the BBA and BRE.

Choice of Finish – Durable, decorative and virtually maintenance free.

The range of finishes available with EWI systems includes a choice of weather resistant, decorative renders offering superb technical performance.

  • Through Coloured Silicone Textured Render – Available in over 600 colours and in 3 different textures.
  • Mineral Topcoat – 1.5mm white textured render that can receive paint.
  • Masonry Paint – Available as a silicone or emulsion paint, for the more traditional looking finish.
  • Dry Dash – Hard wearing traditional pebble dash finish.
  • Rendabrick – Brick Effect render.
  • Traditional Brick Slips – Real brick slips, giving the impression of a traditional brick wall.

Render Finishes



Frequently Asked Questions


How much will it cost?
As property types vary please contact us on 741439 for a detailed quotation.

Do I need Planning Permission?
Due to new Planning requirements, any material change in the roof covering or façade will require Planning Permission before works can proceed. Rateavon can assist you through this process (subject to application costs).

Who installs the system?
Rateavon have a team of trained applicators in all systems.

How durable is the system?
EWI systems have a minimum effective life of 30 years.

Ask us a question…