External wall insulation in North London
External wall insulation wraps your home in an insulating layer, then finishes it in fresh render. The result is a warmer home, lower heating bills, a smarter look and added value, all in one job. Kev Construct Ltd fits EWI across North London and Watford, and it is one of the services our customers rate us most highly for - rated 9.67/10 across 50+ verified Checkatrade reviews.
See the transformation
BeforeAfterRecent EWI projects
What is external wall insulation?
If your home feels cold and expensive to heat, especially an older solid-wall property, external wall insulation is one of the most effective upgrades you can make. We are Checkatrade rated 9.67 out of 10 from 50+ reviews and members since 2019, and our EWI work in particular earns genuine praise.
External wall insulation, often shortened to EWI, is a system fixed to the outside of your walls. Insulation boards are secured to the brickwork, then covered with a reinforced base coat and a decorative render finish. In effect, your home gets a warm, weatherproof jacket that also gives the outside a clean, updated appearance.
It suits solid-wall homes especially well, since these cannot take cavity wall insulation, but it works on many wall types. Because the insulation goes on the outside, you keep all of your internal room sizes, and there is far less disruption inside your home than internal insulation would cause.
External wall insulation & render, Watford
A verified Checkatrade customer in Watford rated this EWI and render project 10/10 - "So happy with the result, neighbours keep commenting. Fast, high standard, friendly and always tidy."
What are the benefits of external wall insulation?
EWI is one of those rare improvements that pays you back in several ways at once:
- A warmer home, with fewer cold spots and draughts and more even temperatures
- Lower energy bills, because your walls hold on to heat instead of losing it
- Better looks, with a smart new render finish that lifts your whole property
- Added value and kerb appeal, which matters if you ever come to sell
- Protection for your walls against wind and rain, and fewer problems with damp and condensation
- No loss of internal space, unlike insulating from the inside
For families who want a more comfortable, better-looking, more valuable home without the upheaval of moving, EWI ticks a lot of boxes in a single project.
How do we fit external wall insulation?
Good EWI is all about careful preparation and neat detailing, and that is where our experience shows. We start by checking the walls and dealing with any repairs or damp issues so the system goes onto a sound surface. We then fix the insulation boards securely, working around windows, doors and pipework with proper beads and detailing.
Next comes the reinforced base coat with mesh, which gives the system its strength and crack resistance, followed by your chosen render finish and colour. Throughout the work, John keeps you informed, and the team keeps the site tidy, which is exactly the experience our Watford customers describe in their reviews. When we finish, we walk round with you to make sure you are delighted with both the warmth and the look.
Which render finish comes with EWI?
The final coat over your insulation is usually a through-coloured render, and silicone render is a popular choice because it is flexible and crack-resistant, sheds water and has self-cleaning properties that help it stay looking fresh. Monocouche and traditional render finishes are also available. We will talk you through the options, colours and textures so the finish suits your home and your taste.
What our customers say.
“John and the whole crew were a pleasure to work with. Fast, great communication, finished on time and to a high quality.”
“Dan and Niko put real care into the work; Marian set everything out clearly with no hidden fees. They went above and beyond.”
“We're an architecture practice and have worked with Kev Construct for years. Reliable, trustworthy, excellent finishes.”
Good to know.
Will external wall insulation really lower my heating bills?
For most solid-wall homes, yes. A large share of a home's heat escapes through uninsulated walls, and EWI dramatically reduces that loss, so your heating works less hard to keep rooms warm. The exact saving depends on your home, its current insulation and how you heat it, but customers consistently notice a warmer, more comfortable home.
Do I need planning permission for EWI?
Often it is allowed under permitted development, but not always, especially in conservation areas or on certain property types, and rules can affect the appearance of the front of a house. We will flag anything that needs checking and can work with your local planning department. It is always worth confirming before work starts.
Will it change how my house looks?
Yes, and usually for the better. EWI adds a fresh, even render finish in the colour and texture you choose, which is why neighbours so often comment, as one of our Watford customers noted. The walls become slightly thicker, so window reveals and sills are detailed neatly to keep everything looking sharp.
How long does external wall insulation take to install?
For a typical house, the work usually takes from one to a few weeks, depending on the size of the property, the weather and any repairs needed first. We will give you a clear timescale with your quote and keep you updated as we go, so you always know what to expect.
Do you guarantee the work?
Yes. We back our work with a £1,000 guarantee, and we are Checkatrade members with a 9.67 out of 10 rating from 50+ reviews. We also undertake insurance work. Our EWI reviews from Watford give you a real sense of the standard you can expect.
Want a warmer, smarter,
more valuable home?
Ask for a free external wall insulation quote today. You'll get a clear price in writing - with no pressure and no hidden fees.
- Free home visit & survey
- Fixed price in writing - no surprises
- Local Edgware team · rated 9.67/10 on Checkatrade
Prefer to talk? 07838 662 225