What is External Wall Insulation (EWI)?

External Wall Insulation from Caparol coats your property with solid insulation material. The insulation is supplied in boards, which are mechanically fixed to the exterior. A basecoat is then applied, followed by a primer and finishing render chosen from a wide range of textures and colours to achieve the appearance you want. It’s particularly suitable for solid-walled properties, properties with narrow, irregular or damaged cavities, and for non-standard constructions. It also delivers great results on commercial buildings.

How does External Wall Insulation work?

External Wall Insulation hugely reduces the amount of heat lost through the walls of your property by trapping heat, preventing it from escaping to the external atmosphere. The insulation boards that are part of the system installed by P3 have superior resistance to heat transfer, so more of the heat you put into your property stays where you intended it to. Technically, the u-value of your walls is being reduced (typically from 2 currently to 0.3 once EWI has been installed). A u-value is a measure of how much heat is transferred through a given material; the lower the value, the lower the heat transfer.

How long does External Wall Insulation take to install?

A typical installation takes 2-4 weeks. P3 will ensure sufficient installation teams are employed to achieve this, regardless of the size of the building. The installation is weather-dependent though. The basecoats and renders cannot be applied when the outside temperature is below 5°C, nor in periods of very extreme hot weather. Also, the system should be protected from the rain. We will take all steps to protect your installation, but there may be times when we have to withdraw from site due to extremes of weather. This is always taken into consideration by the P3-approved installer team and any rescheduling will be clearly communicated to you.

Will there be any disruption for me or my tenants?

P3 is committed to making any installation as smooth as possible. All work takes place on the outside of your building so you can live in the property as normal during installation. And, we can ensure that TV reception is not interrupted by arranging temporary fixing of the satellite dish or aerial during installation.

How long will it take to complete the installation and will it be disruptive?

Installation usually takes in the region of 2 weeks and as all works are external, disruption will be kept to minimum.

What about fixing new things to my walls, e.g. a hanging basket?

You will need to use fixings that penetrate through the external wall insulation and into the substrate of the building, i.e. the original wall. P3 can supply these – simply speak to us when the need arises.

What about my satellite dish and other external fixtures?

After removing any external fittings to allow us to apply the system, P3 will fix plates to the wall of your property before applying the insulation, render and finishing coat. These plates will be sized to ensure your external fittings can be re-fitted securely.

What colours can I choose for my External Wall Insulation?

Caparol can offer a wide range of colours, allowing you to create a traditional or contemporary appearance. We would be happy to advise you on available finishes and suitable colour options during your Free survey. To arrange a visit to discuss your needs, simply complete our Contact Form.

I live in a semi-detached property – what if my neighbour doesn’t do it as well?

We can offer a choice of methods to achieve a clean and neat break between your properties. The fact that the adjacent property hasn’t been treated to External Wall Insulation will not affect the energy-efficiency improvements (and reduced heating bills) you will enjoy.

Is there a portfolio of finishes available or is it only smooth render?

There is wide portfolio of finishes available including brick, plus a vast range of colours and textures in rendered finish.

Future upkeep

How long does External Wall Insulation (EWI) last?

P3 and Caparol only install systems recommended by the Energy Saving Trust which must demonstrate a life expectancy of at least 36 years. We are aware, however, of systems installed 57 years ago which are performing as installed.

Will I need to paint the outside of my home in future?

Modern technology external wall insulation has revolutionised the need for exterior painting. Using “next generation” Caparol self-cleaning finishes, the exterior of your home stays clean and vibrant for many years without any need for painting or maintenance.

What about maintenance of External Wall Insulation?

The exterior finishes are designed so they do not allow the growth of mould. Maintenance should be limited to the need to wash down occasionally to maintain an “as-new” appearance.

What if my wall gets damaged after installation?

Your external wall insulation system will withstand typical knocks and bumps. In the unlikely event that it is damaged by a very hard impact, repairs can be easily completed.

What about my window sills and drainpipes?

The addition of External Wall Insulation to your property will increase the thickness of the walls. P3 will add extensions to your windowsills so that any rainwater is deposited clear of your new exterior finish. Your downpipes will also have to be removed so that your system can be applied – we will re-fit these afterwards, including any additional or replacement fittings to accommodate the new wall dimensions.


How do I know my property is suitable for external wall insulation?

Most properties built before 1920s have solid walls. With solid wall properties there is no cavity to fill, hence external wall insulation is often the most cost-effective home efficiency improvement.

My home is damp, does External Wall Insulation help with this?

Yes. The primary cause of damp within any home is condensation. Condensation forms when moisture laden air comes into contact with a cold outer wall. External wall insulation creates warm interior walls and prevents the condensation from happening. The result is a warm, comfortable and healthy home.

I would like to replace my windows, should this be done before or after installation of EWI?

Windows can be replaced at any time however if you intend to do both together (as is sensible as scaffold is already up) it is easier to install windows first.

Do I need Planning Permission to fit External Wall Insulation?

Generally, Building Regulations will apply, but P3 can advise and assist you to make the necessary applications.

Is External Wall Insulation suitable for non-standard buildings?

External Wall Insulation is ideal for many types of non-standard buildings. After World War 2, there was a push for new housing, which drove the development of many different designs, many of which featured pre-cast concrete panels. These panels are thermally-inefficient, allowing a lot of heat to be transferred from the inside of the building to the external atmosphere. By adding a Caparol EWI (external wall insulation) system to this type of property, huge gains can be made in energy-efficiency, with improved comfort levels together with significant savings on heating costs.

Is External Wall Insulation suitable for timber-frame buildings?

P3 can install a system to suit a wide range of constructions, both refurbishment and new-builds including timber-frame and steel-frame. If refurbishing, EWI will greatly improve the thermal properties of this construction-type and make the building easier (and cheaper) to heat to a comfortable level. If using frame construction on a new-build, External Wall Insulation is particularly suitable, as the very high insulation values compliment modern building requirements. Plus, as the application is quicker than traditional “wet-walls”, the building can be occupied or marketed more quickly.

Finance & Specifications

How much does External Wall Insulation cost?

Each property will have specific requirements, so it is difficult to give a guide-figure. Instead, P3 commits to giving you a free survey and quotation so you will have an exact figure, so you can budget from your own resources or explore our finance options with our help. Simply contact us to arrange your free external wall insulation survey.

How much will I save if I install External Wall Insulation?

This depends on many factors: the type of fuel you currently use, how warm you want you keep your property, which Caparol External Wall Insulation system you choose, and many other factors. Check out our energy saving calculator for an approximate cost saving. We would give you a guide following your survey, but please be aware this can never be a wholly accurate forecast due to the many influences beyond our control or yours. What you can be assured of, however, is that you can easily achieve walls that are as efficient as those in a newly-built property (or better), meaning you are reducing the heat lost through your walls to the minimum.

What insulation material is used in an External Wall Insulation system?

Caparol offers a choice of EPS (expanded polystyrene) and Mineral Wool insulation. Each has different properties, you will find an overview here. We will be able to establish the right type for you when we visit to perform your free survey.

What finishes can I choose for my External Wall Insulation?

You have a wide choice of systems that include smooth paint, rough texture and brick-slips.

How thick will my External Wall Insulation be?

Caparol provides systems to suit all property types, and the thickness of the covering will be dependent on the needs of the individual building. As a very general guide, an installation will commonly require a 90mm thick insulation board, plus the basecoat and final render finish, which will be approx. 15 mm. We do, however, supply insulation boards from 20mm to 400mm, depending on requirements. Your free survey will identify the most appropriate thickness.

What guarantees will I have with external wall insulation?

You will receive a 10 year product and workmanship guarantee.

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P3 Facades & Interiors

Unit 5 Pitronnerie

Industrial Estate

Pitronnerie Road

St Peter Port



United Kingdom

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+44 (0)1481 740 396

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