What is External Wall Insulation?” & Other Questions

Here at Baumit, we’re the external wall insulation experts and we’re here to answer all of your questions. 

If you’re looking to install external wall insulation on your property, but aren’t quite convinced, or have some doubts, you’ve come to the right place. Modifying the exterior of your home can seem like a huge commitment or even a risk. However, we can show you that the benefits vastly outweigh the drawbacks when it comes to external wall insulation.

Even if you’re just curious about EWI, read through the questions below for a staple introduction to our products and systems. 

What is external wall insulation? 

When stripped down to its simplest form, external wall insulation (sometimes known as ‘EWI’ or ‘ETICS’) refers to the placing of insulating materials on the outermost surface of a building. 

But, in reality, it’s far more complex than that. 

External wall insulation consists of a series of insulating layers in the form of boards being placed on the external surfaces of all of the vertical walls of a structure. This procedure is suitable for almost all property types, from new builds and extensions looking to achieve a certain energy efficiency level, to unconventional buildings without cavity walls. 

This insulation process is aimed at protecting the building from all sorts of factors, including (but not limited to): 

  • Fluctuating weather conditions such as excessive heat and cold spells 
  • A loss of heat from inside the building 
  • A change in internal climate on account of external temperature changes 

But EWI does more than that. It also helps reduce energy consumption by modulating internal climate independently from heaters and cooling systems such as air conditioning units. As well as this, it helps keep the inside of a property cool in the summer and warm in the winter as desired. 

What is EWI made of?

Insulation boards form the core component of an external wall insulation system and can range in thickness and style. You can browse our full range of insulation boards here. 

Some, like our Mineral Wool Insulation Board,  are made from vapour-permeable, non-combustible wool. Others are comprised of perforated EPS boards like our Baumit openTherm. Find out more about our breathable EWI here. 


Why choose external wall insulation?

While there are numerous reasons why homeowners chose EWI time and time again, a few continue to stand out. 

Firstly, people are often drawn to EWI because of its heat- (and therefore money) saving potential. The very point of insulation is, well, to insulate. And External Wall Insulation happens to do this very well! 

Acting as a barrier to prevent the cold air from even reaching the actual walls of your home, EWI keeps the inside of your home warmer in winter (and vice versa in summer).

This greater resistance to the changes in external weather means homeowners will become less reliant on artificial heating and cooling systems — so you can say goodbye to air conditioning and radiators on full blast! 

Another reason you might like to opt for EWI is the visual aspect. If you are renovating your property, what’s one more step to improve its efficiency and exterior aesthetics? 

Due to the customisability of Baumit’s EWI systems, installing it on your home opens up hundreds of design and architecture possibilities. Take a look at some of the recent projects that have used our EWI systems for some inspiration. Our Baumit Star Therm Nature, for example, was used on these beautiful properties.

Read our blog on why you should choose EWI to find out more.

Does external wall insulation (EWI) need planning permission?

No, there is no need to obtain full planning permission for the installation of external wall insulation. It does not change the structural configuration or safety of a property — if anything, it enhances it. 

That being said, if the property you want to insulate is located within a conservation area, you will need to obtain planning permission. What’s more, as with any type of renovation or restoration work, listed buildings will need to have planning permission in order to go ahead with renovations. 

If you are unsure what category your property falls under, it is worth checking with your local planning institute to avoid any nasty surprises further down the line. 

What are the benefits of External Wall insulation?

Fitting external wall insulation on a property brings with it a whole host of advantages, including (but by no means limited to) the following: 

Spend less on heating 

The main reason why homeowners are often drawn to EWI is its financial saving potential. This is because it helps regulate the interior climate of your home. EWI maintains a steady internal climate irrespective of the external weather conditions all year round. 

By allowing you to use less electric heating throughout the year, EWI also helps reduce your carbon footprint!

Protect against the elements 

With external wall insulation, you can experience fewer draughts and greater comfort in your home as the insulation boards cover all gaps that let wind in (and heat out) previously. 

EWI also reduces the risk of condensation forming on your internal walls, in turn helping to lessen the chances of your house developing a damp problem. If the climate in which you live is notoriously humid, external wall insulation is a great option.

Your external walls will also be protected from the elements. This is optimal for areas in which the climate is extreme — cold or hot. This way, your walls will become far less susceptible to wear and tear such as freeze-thaw and cracking in the heat, extending their lifespan.

It’s everything-proof 

Alongside weather-proofing, external wall insulation is also known to be soundproof. This is optimal for homeowners who may live near busy roads or in built-up areas. On top of this, EWI also boasts a fire-proof quality that can help to keep your home safe.

No disruption whatsoever 

The installation of EWI has no impact on the day-to-day running of your home. Having EWI allows you to enjoy a larger floor area inside your home. Since the thick insulation boards are applied to the exterior of your property, you will be losing no floor space inside. 

It looks great 

External wall insulation gives the exterior of your home an enhanced aesthetic. By adding a layer of fresh materials over your existing walls, your property is essentially treated to a ‘facelift’ by revitalising its out-facing surfaces. 

You can choose from a whole range of our renders to transform the outside of your property. And, if you’re stumped on what kind to choose, you’d best believe we have a guide for that too. 


Contact Us

If you have any further questions about external wall insulation boards or systems, either get in touch with the experts at Baumit or read through our EWI Information Booklet