Frequency Asked Questions


What 3rd party certification does Baumit currently hold?

Baumit hold various BBA Certificates and European Technical Assessment (ETA) Certificates. These can be found on our website here. Alternatively, contact our technical team to request a copy of one of Bamit's 3rd Party Certificates on technical@baumit.co.uk

Does Baumit have ISO 9001 & 14001?

Baumit are proud to be ISO 9001, ISO 14001 and ISO 45001 certified. To find out more, you can contact us on contact@baumit.co.uk

Where can I find the names of your approved contractors?

You can find the contact details of your local approved installers by requesting them via contact@baumit.co.uk

How do I become a Baumit Approved Installer?

We currently have two training academies in the UK. One in Maidstone, Kent and the other in Doncaster, South Yorkshire. You can see what sessions are available at your local academy by visiting the Training page

External Wall Insulation

What is External Wall Insulation (EWI) / ETICS? 

External Wall Insulation (EWI) is the placement of insulating boards on the external surface of all the vertical walls of a building. This protects the building from fluctuating weather conditions, reduces heat losses from inside the building and will prevent external temperature changes from affecting the interior climate. EWI keeps homes warm in winter and cool in summer, ensuring a home with a pleasant atmosphere by eliminating sharp and high changes in indoor temperature. EWI will also reduce energy consumption terms of energy consumed for heating and cooling.

Why External Wall Insulation (EWI)?

Initially, the main reason for choosing an External Wall Insulation solution is that EWI will achieve higher thermally insulating results by protecting the walls from changes in outdoor temperature, taking advantage of the thermal capacity of the existing walls and more effectively avoiding thermal bridges. 

Therefore, with EWI, the maximum possible reduction in heating or air-conditioning costs can be achieved. Another reason for opting for EWI is to enhance renovations. If renovating the exterior of a building, opting for an EWI solution provides great flexibility for architectural and design choices. 

The disadvantage of indoor thermal insulation is the reduction of floor space in the house from the installation of the thermal insulation. In addition, the decommissioning of any objects found on the walls such as built in storage, wardrobes and radiators for example, and their subsequent reinstallation is time consuming and costly. 

What insulation boards are used for External Wall Insulation (EWI)?

The standard materials used as part of the Baumit EWI systems are Expanded Polystyrene (EPS), Mineralwool, phenolic insulation and wood fibre boards. More information can be found here.

What thicknesses of Insulation should I use?

The most common insulation thickness is 100mm, however a U Value check can indicate the appropriate thickness you will require. 

How does External Wall Insulation (EWI) fit around existing pipes and services?

When installing EWI, all pipes should be extended and then returned into the existing outlets. Utility services should be treated according to the guidance of the utility provider.

Do you have a system for the plinth area??

As part of our External Wall Insulation system range we offer a specifically design Plinth System which uses a High Density insulation Board.

For further information you can visit our PlinthSystem guide here

What final finishes are available to complement the External Wall Insulation (EWI)?

Baumit has a variety of mineral and organic topcoat renders suitable for use will all our EWI systems, each available in a huge range of colours. 

Please refer to the Baumit Topcoats leaflet for our full range of renders.


Can Baumit render be tinted to any colour? 

With over 1000 colours in the Baumit Life range, we are confident we can find you the exact colour you are looking for. However, some of our renders are only available in certain colours. To find out which render you need, visit the World of Life Colours section.

Are all Baumit render products sprayable? 

Yes, all of the products in our render range can be spray applied. 

Can I add water to a topcoat to make it easier to apply? 

Yes, we would recommend no more than a cupful (5% of the product).

Environmental Impact

How much money can having EWI save me? 

This is mostly dependent on the size of the property that the EWI system is being installed on. Cost savings on energy bills can range from £500 - £1,000 per year.

Does EWI reduce CO2? 

Simply put, having EWI installed on a property will reduce the levels of CO2 produced from a property. For example, EWI on a concrete construction can save up to 24kg of CO2 per 1m2. For a brick built property, up 10kg of CO2 can be saved per 1m2.

Do you consider your carbon footprint within your manufacturing process? 

Sustainability is very important to everything that Baumit does. We are constantly looking at ways in which we can help to reduce our carbon footprint and become carbon neutral, in the near future. Our carbon footprint is helped to be offset by the very thing that we are passionate about; External Wall Insulation systems. Since Baumit was incorporated in 1988, we have installed approximately 810 million square meters of EWI, across Europe. This equates to approximately 14.5 billion tonnes of CO2 saved across a 35 year period!


Does External Wall Insulation (EWI) need planning permission? 

There is no need for full planning permission to install EWI, unless you are living in a conservation area or a listed property. However, always check with local planning authority to be sure.

Can I get a warranty on my Baumit render system? 

Baumit are happy to offer product warranties and system warranties. To find out more on how to qualify for a Baumit Warranty, contact us on contact@baumit.co.uk

Where can I find the product data sheets? 

These can be found on our website, under each individual product. Alternatively, contact our technical team to request a copy of our data sheets technical@baumit.co.uk

Can I render over a painted substrate? 

Depending on the condition of the paint, Baumit do have products within our range to cope with a direct application over the façade. (MC55 W) Usually, a ‘scrim and pin’ system would be recommended when installing a render system over an existing painted surface.

How do I access Baumit’s technical drawings? 

To request a copy of Baumit’s detail drawing set, you can contact our technical team on technical@baumit.co.uk

Do Baumit offer U-Value and Condensation Risk reports? 

Our in-house technical team have undergone the relevant U-Value Assessors course and are therefore able to offer U-Value and Condensation Risk Analysis. You can send your request through to our Technical Team by e-mailing technical@baumit.co.uk

What thickness insulation do I need to achieve Building Regulations? 

The thickness of insulation required on a building is dependent on each project’s guidelines. The thickness required will be determined by the target U-Value set out by building regulations, the wall build-up and the insulation type. 

What topcoat should I use with my render system? 

Baumit offer a wide variety of topcoat renders including, Acrylic, Silicone and Lime. Each project will have its own requirements as to the most suitable finish dependent on local environment, building age, construction type and aesthetics. Speak with our technical team to find out more via technical@baumit.co.uk

Can I install External Wall Insulation (EWI) on a cavity filled property? 

External Wall Insulation (EWI) is designed for a solid wall construction. You will need to seek further advice from a cavity extraction consultant for your specific needs.  


Do I need to use a movement joint within an EWI system? 

The architect would typically specify the required locations of movement joints, but as a minimum requirement, movement Joints should always be mirrored through the EWI system when there is a structural movement joint existing in the building.

How many fixings do I need in my EWI system? 

This is dependent on the system, construction type, local environment, building-regulations and so on. Typically, a minimum of 6 fixings per 1m2 is required on residential properties below 11m in height. Contact our technical team on technical@baumit.co.uk to find out more.

How long does the installation of an External Wall Insulation (EWI) system usually take? 

Depending on the size of the project, usually a two-week period is enough to complete the project.

What weather conditions can I apply Baumit render in? 

Baumit renders shouldn’t be applied in temperatures of lower than 5°C and higher than 30°C. Primers, paints and topcoats should not be applied if rain is forecast within 48 hours of application. Finally, humidity levels of <80% can greatly reduce the curing time of render products and is therefore an extremely important thing to consider when timing your installation.


Is your render self-cleaning? 

We don’t offer a ‘self-cleaning’ render within our product range. Our external finish coats are designed to be weather resistant, and some are dirt repellent. (This doesn’t mean that they stay looking brand new forever, the façade will need cleaning and maintenance when required) You can view our range of topcoats here (link to web page)

How do I clean render on the outside of my house? 

Silicone and acrylic based render systems can be cleaned using a pressure washer at no closer than 1m away from the wall. Pressure washing is effective for when there is build up of dust/ dirt on the façade. It is always recommended to complete a small area, in a discreet location first to assess the effectiveness and to ensure no damage will occur. 
Warm soapy water is another option for cleaning small areas of dust/ dirt, scuff marks etc.. Complete a small test area first.
For areas where there has been a build up of algae/ natural growth on the walls, Baumit FungoFluid can be used to aid the cleaning process. 

The final option is applying a full covering coat of Baumit Silicone/ Acrylic Paint. A full elevation should be painted to avoid leaving patchy areas.