External Wall Insulation Benefits

What is External Wall Insulation?

External wall insulation is an additional outer layer of insulation and exterior cladding fixed to an existing solid wall, used to improve the thermal insulation of a building and increase protection from weather and elements. 

The external insulation slabs that are installed improve insulation performance and are non combustible mineral wool slabs that have water resistant benefits.

External wall insulation improves the air overall, meaning it doesn’t just provide and retain warmer during the winter, it also improves the quality of the air during the summer and prevents stuffy, clammy conditions. 

External wall insulation is also commonly known in the trade in Scotland as “EWI” or “external solid wall insulation”.

External wall insulation systems are available in a range of colours and designs to match with your homes roughcasting, render and the rest of the exterior.

Government grants are available for external wall insulation via Home Energy Scotland, with £7,500 funding available and a further £2,500 interest free loan. Our partner installers can assist you with an installation using a government grant.

How does External Wall Insulation Work?

Installing (EWI) external wall insulation on your home is one of the best ways to save on energy bills and retain heat. Once you do this effectively it takes less energy to heat your home, saving you hundreds of pounds on heating bills each year and improving your homes energy efficiency rating (EPC).

Insulating your external wall is the best form of home insulation and most effective in terms of increasing thermal efficiency of houses with solid walls. A high percentage of homes in Scotland have solid walls (not cavity) especially older builds, making external insulation the best way to go the vast majority of the time.

Do I need planning permission to install external wall insulation?

Yes, sometimes you will need it, some listed buildings and conservation areas require planning permission for ewi to be installed, this is almost always granted though due to the benefits of external insulation and the ease of the installation.

External Wall Insulation Glasgow

See pictured an external wall insulation job completed in Glasgow. Our partner installers also applied new external rendering, which along with roughcasting is another specialist area for them.

On most occasions when you are considering a quote for external wall insulation it makes sense to have a package including the roughcast and render too, as this is the most outer layer of your external walls.

For this job, the team remove the existing old roughcast, stripped back the walls and installed external wall insulation, before applying a smooth white render with colour co-ordinated grey sills and wooden ledges.

We think you will agree this looks  stunning and the external wall insulation will provide all of the heat retention and insulation benefits.

External wall insulation and render in Glasgow

External Wall Insulation Edinburgh

Here’s another recent project featuring the installation of external wall insulation in Edinburgh. Our partner installers also completed the application of new external rendering after this photo was captured.

We’re sharing this image to highlight the external wall insulation before the render is added on top.

In this job, our team once again removed the existing old roughcast, or “harling” as it’s known in Edinburgh, stripped back the walls, installed external wall insulation, and then applied a smooth white external render.

External wall insulation in Edinburgh

External Wall Insulation Dundee

For this external wall insulation installation in Dundee, again the installers fitted an EWI system and roughcasting. 

See from the gallery of pictures, several steps of the work, clearly showing both the external wall insulation and Sky Marble roughcast on top of a white top coat.

The window cills and base, facia and soffits were painted grey and the gutters and downpipes painted black.

Types of External Wall Insulation

Mineral Wool

Mineral wool is the type of external wall insulation that we install, Knauf is the brand. For EWI mineral wool is compressed into an insulation board that is fireproof, soundproof and carries all of the same benefits as any other mineral wool insulation which happens to be the worlds most popular type of insulation (and for good reason!).

(EPS) Expanded Polystyrene Insulation

Expanded polystyrene external insulation is a bit like it sounds, polystyrene is compacted together creating a solid insulation board. It’s a lightweight type of insulation, however it comes with varies risks and cons, hence we choose not to install it!

Wood Fiber Insulation

Wood fibre is the most eco friendly and sustainable insulation, making it appealing to people looking to reduce their carbon footprint, however, it is only really suitable for timber framed buildings and things of this nature.


Although not officially insulation, roughcasting is applied to your external walls and does have insulation benefits. After being installed, your homes roughcasting is the very outer layer of your walls and is ideal for this purpose due to it being so durable and weatherproof.

External Rendering

Much like roughcasting, external rendering acts as external insulation but looks much better than roughcasting, both provide another layer of protection for your walls from the outside elements.

Knauf External Wall Insulation

The type of external wall insulation we install is a Knauf system. Knauf insulation is a worldwide brand and the market leader in Scotland, the United Kingdom and Europe. Their head office based at Stafford Road, Saint Helens, WA10 3L, click here to visit their Google Business Profile.


Other Types of Home Insulation We Install

Insulation Scotland work with specialist insulation installers, installing all types of insulation for homes and businesses across Scotland. Our installers work from across Scotland, meaning we can comfortably serve the whole country with the following types of insulation:

 · External Wall Insulation

· Solid Wall Insulation

· Loft Insulation

· Underfloor Insulation

· Roof Insulation

· Room in Roof Insulation

· Internal Wall Insulation

· Cavity Wall Insulation

Solid Wall Insulation Scotland

If it’s an external wall, solid wall insulation is really just another term used for external wall insulation. However, solid wall insulation can also apply to internal wall insulation mainly applying to solid brick, stone and other popular materials that the structures of the walls of homes in Scotland are made from. 

With regards to internal wall insulation, needless to say it doesn’t cover cavity wall insulation, however, we are asked this often. The insulation of cavity walls requires a totally different and unique form of installation.

Because there are so many types of wall surface, there is no way to give an accurate cost for solid wall insulation without conducting a free, no obligation home survey to establish wether its internal wall, cavity wall or external wall insulation that’s most suitable.


Can you insulate a solid stone external wall?

Yes, we can help you insulate a solid stone external wall. It just requires the correct primer and preparation so that the external insulation material bonds with your wall and creates an air tight seal.

Does External Wall Insulation fix damp?

Yes, external wall insulation can fix damp, however, other work has to be carried out before it is installed in order for it to be effective. Obviously, simply installing EWI on the outer surface of a wall that has damp issues will not resolve your problem. If your wall has damp issues, we need to find and fix the root cause which generally will either be your render, roughcast or your brickwork.

Once we establish what causing the dampness in your walls, we will provide you with a quote to fix this and install external wall insulation on the outer surface to make sure this issue never presents itself again.

Does External Wall Insulation Stop Draughts?

Yes, external wall insulation can stop draughts, however, much like issues with dampness in wall, we have to establish all of the causes that are contributing to any draught issues.

Installing external wall insulation will compliment any other forms of draught proofing and insulation you already have. Debatably external wall insulation is the most effective method of both insulation and draught proofing.

Benefits of External Wall Insulation

Some of the benefits of external wall insulation are briefly listed above, here is a longer list of benefits that it provides:

External Wall Insulation Cost in Scotland

Depending on the type of home you are living in, installing external wall insulation could help your reduce your energy bills by several hundred pounds each year (on average). The payback time is much less if you previously never had any insulation at all.

The houses people in Scotland live in can generally be divided into three types, terraced, semi-detached, and detached.

According to the data provided by the Energy Saving Trust, the average cost of external wall insulation varies but tends to be in the tens of thousands. An average semi-detached home in Scotland can cost between £12,000 to £15,000 to have external wall insulation installed. The size of the property affects the costs and the fact you need to install new roughcast or render on the outer layer of the walls.

It’s almost impossible to provide you with a cost for external wall insulation without knowing more information about the size of your home. Even when we know the size, each ewi installation is different depending on other factors. In order to arrive at an accurate cost for external wall insulation you need to have a free home survey completed.

External Wall Insulation Grants Scotland

There are grants available too for external wall insulation almost always resulting in reduced costs for external wall insulation, with up to 75% off the costs or £7,500 off available.

External wall insulation grants are awarded through Home Energy Scotland, The Great British Insulation Scheme and the Governments ECO 4 grant scheme. To qualify for any of these grants, your home must fall below a certain energy performance certificate (EPC) rating.

Insulation Scotland

External Wall Insulation Installers Scotland

There are not a huge volume of external wall insulation installers and companies based in Scotland, it’s quite a specialist trade. You should always carry out your own research to make sure you select the best installer for insulating your home. Also, you should always check for ratings and reviews on the web and choose a well established external wall insulation company.

There are only a small handful that can provide installation via government grand funded work.

Our External Wall Insulation Installation Process

1. Test your render.

Allowing us to make sure your render is capable of supporting an EWI installation. Should your render be strong enough, we will smoothen it in preparation for installation or completely remove it if required.

2. Removal or adjustment of pipes.

Your pipework is often removed from your home prior to installation.

3. Windows and doors protection.

During every EWI installation we add a protective film over your windows and doors to prevent any damage.

4. Starter track installation.

We install an aluminium start track which helps ensure the height of your insulation installation.

5. Insulation boards installation.

We attached insulation boards using adhesive which bonds between the board and your wall.  We often file off the edges of the boards to ensure its completely flat. 

6. Installation mechanical fixings.

This part of the process make sure your insulation boards are solid and rigid with no gaps in-between. 

7. Beading installation.

We make sure your external insulation is air right be corner beads and stops beads are soundly installed. 

8. Supporting mesh and render.

In some cases we can install fibreglass mesh in-between each layer of render to further strengthen your insulation.

9. Add some primer.

If required, primer can help your final coat stick to the ewi boards and other layers of your external walls.


Insulation Scotland

Fully insured EWI Installers

Facts About Scotland

1. Scotland population in 2024 is estimated to be over 5.51 million people according to wikipedia.

2. During the first quarter of 2024, Scotland’s GDP has grown by 0.7%!

3. External wall insulation in Scotland is becoming increasing popular alongside roughcasting which is the most popular type of external wall coating.

4. Here is the top 3 places to visit in Scotland from a list of 8 on visit Scotland.

1. Dunbar, East Lothian –  Been there myself many times and it’s views galore, you could sit on the cliffs all day watching the waves so I can see why it’s places first.

2. Isle Of Raasay, North Highlands – never been myself, heard great things apparently the most beautiful island of the outer Hebrides along with the Isle of Skye.

3. Aberfeldy, Perthshire – I’ve drove past but disappointed to say I’ve not been in the area to see the amazing waterfalls, country walks, apparently The Birds Of Aberfeldy are the stand out landmark.

Get a External Wall Insulation Quote

Please fill out the contact form below so we can arrange a no obligation external wall insulation survey. Please allow up to 48 hours for one of our representatives to contact you to discuss on the telephone.

EWI Quote in Scotland

Please call us to discuss your requirements, if you have pictures of the outside walls of your home please send these too.

External Wall Insulation Across Scotland

Our team of external wall insulation contractors and surveyors travel all over Scotland providing our services in Aberdeen, Aberdeenshire, Angus, Argyll & Bute, Ayrshire, Clackmannanshire, Dumfries and Galloway, Dundee, East Ayrshire, East Dunbartonshire, East Lothian, Edinburgh, Glasgow, Falkirk, Fife, Highland, Inverclyde, Inverness, Midlothian, Moray, North Ayrshire, North Lanarkshire, Perth and Kinross, Renfrewshire, Stirlingshire, South Ayrshire, South Lanarkshire, The Borders, West Dunbartonshire and West Lothian. 

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