External Wall Insulation

What is External Wall Insulation?

External wall insulation is installed by adding a weatherproof insulating layer to the outside of your wall. This could be in the form of a protective render. The thickness of the insulation is usually between 60 and 100mm thick. The materials used for external wall insulation are often referred to as a "system" because there are three layers that must work together. The insulation material, the framework and the finishing layer.


  • BBA Approved
  • Weather proof
  • Average saving of £450 - £500 on fuel costs per year
  • Reduced heat loss in winter and reduced overheating in summer

How does it look?

The Work Schedule


Erection of scaffolding


Plumbing on external walls (e.g. Soil pipes from the bathroom & gas flues) will be extended to accommodate the insulation boards.


External fixtures (e.g. alarm boxes, lighting, hanging baskets) will be removed. Wooden blocks will be fitted to your wall to make it easier to refit your fixtures so that they are put back in the same place once the insulation has been installed.


Installation of insulation board (Estimated at 1 to 2 days)


Render 1st, 2nd and 3rd coat. The second coat can look like the painted finish but it is a base layer. Please note: each layer of render requires a drying time. Hence the installers will not necessarily be at your property everyday, as they need to allow 4 drying times, plus this work must be done in dry frost free weather. Window sills will be temporarily fitted at this stage and protected with polythene film.


Upstairs windows will be finished with an insulated UPVC strip above the top of the window.


Window sills will be attached and sealed with silicone.


External fixtures (e.g. alarm boxes, lighting, hanging baskets) will be refitted.


Snagging report. All work will be reviewed and minor alterations noted and completed. Please highlight any concerns to our Quality Inspector that you have at this stage.


Cleaning of the windows, doors, down pipes and ground will be completed by the installer.

Sign Off

Rockwarm will sign off the work in accordance with the terms of the contract.


Scaffolding will be taken down.

Your property will be regularly visited during the installation by one of our Quality Inspectors. Their role is to assess the quality of the installation at key stages and ensure that Rockwarm’s Health & Safety guidelines and procedures are being followed at all times.

Instant Online Quotations

We are more than happy to answer any of your questions. Installing EWI and render is a big job that requires careful consideration before going ahead. That’s why we are always pleased to advise customers as to the best options for their particular property. If you are looking for a quote, please contact us via the form below to get a quick, free, no obligation response. If you prefer to contact us directly - please call us now on 02476 345554