Services
External Wall Insulation
External wall insulation is one of the biggest upgrades you can make to a home — warmer rooms, lower bills and a brand-new façade in a single project. Our approved teams manage the whole system, from U-value survey and grant advice through board-fixing and reinforcement to the render finish, delivered to a standard that passes building control and lasts.
How we work
Survey & U-value calculation
We assess the wall build-up, calculate target U-values and advise on grants — EWI on solid walls is where funding usually applies.
Board fixing
60–150mm EPS, mineral-wool or phenolic boards mechanically fixed and adhered, staggered joints, corners reinforced.
Basecoat & mesh
Full reinforcement layer over the boards — the structural skin of the system.
Render finish
Silicone or mineral topcoat in your chosen colour — your home is warmer AND looks brand new.
Certification
Building-control sign-off where required, warranty registration, and the paperwork lenders and buyers ask for.
Real external wall insulation projects
External wall insulation — recent Namis Facades project
External wall insulation — recent Namis Facades project
External wall insulation — recent Namis Facades project
External wall insulation — recent Namis Facades project
External wall insulation
Premium External Wall Insulation Services
If you are looking for professional external wall insulation, Namis Facades provides an unparalleled, turnkey solution for your property. We partner with industry-leading manufacturers—including PRB, Weber, K Rend, PRB, SAS, and Fassa—to deliver a wide range of colours and high-quality finishes
Our Surrey-based EWI installation teams boast 5 decades of combined expertise. We leverage our in-house teams of experienced, fully certified installers to assume full responsibility for the render finish on every project we undertake. Past clients highly praise our meticulous attention to detail and respectful approach to working on their properties.
What is External Wall Insulation?
External wall insulation (EWI) is a highly effective thermal upgrade system applied to the exterior of a building. It involves fixing an insulating material to the outside walls, which is then covered with a protective, weather-resistant render finish. This system significantly reduces heat loss, lowers energy bills, and improves the aesthetic appearance of your property.
Types of External Wall Insulation Materials
We supply and install all major types of external wall insulation materials to suit your specific property needs, including:
- Mineral Wool Insulation Boards: Excellent for fire resistance and acoustic insulation.
- Expanded Polystyrene (EPS) Boards: Highly cost-effective, lightweight, and thermally efficient.
- Phenolic Insulation Boards: Premium insulation offering the highest thermal performance with a thinner profile.
EWI Render Finishes: Multi-Coat vs. One-Coat Systems
Once the insulation boards are installed, we offer two primary types of render finishes:
1. Acrylic and Silicone Multi-Coat Systems
A multi-coat system is a high-performance external wall insulation system protected by mesh-cloth reinforced polymer renders. This method benefits from being "self-cleaning," highly flexible, and crack-resistant.
The Multi-Coat Process:
- Apply a 2-4mm base coat.
- Embed an alkaline-resistant reinforcing mesh.
- Apply a second 2-4mm layer of base coat.
- Once dry, apply a specialised primer layer.
- Finish with a coloured texture coat once the primer is touch-dry.
2. Mineral One-Coat Systems
Through-coloured mineral render systems offer a specially formulated mineral-based render that can be hand or machine-applied directly to all major insulation types.
Because it is a one-coat system, there is no waiting for a base coat to dry. The material can be applied rapidly using a spray render pump, making the application highly economical. Fibre mesh reinforcement is applied between wet passes, and the material is finished to a scraped texture the following day. This significantly reduces scaffold hire costs and minimises disruption to the homeowner. The resulting finish is maintenance-free and available in a wide range of colours and textures.
Visualize Your ProjectIf you would like to visualize your project’s appearance in different colours and shapes, our Facade Colour Simulator is here to help. You can try out various colours for your EWI, silicone render, or monocouche render finish before making a decision.
The EWI Installation Process: Step-by-Step
Every project is executed by our team of EWI professionals who adhere to the utmost standards of quality. The external wall insulation installation process typically includes the following steps:
- Site Preparation: Setting up scaffolding to ensure correct and safe access.
- Waste Management: Arranging a waste skip for large projects.
- Property Protection: Installing protection for windows, doors, soffits, rainwater systems, and other external elements.
- Board Installation: Fixing the chosen insulation boards securely to the exterior walls.
- Base Layer Application: Applying mechanical fixings, the first base coat, and alkaline-resistant reinforcing mesh.
- Top Coat Application: Applying the final coloured texture coat of the customer’s choice.
- Site Cleanup: Disposing of waste, thoroughly cleaning the working area, and removing the scaffolding.
Why Choose Namis Facades?
This comprehensive service extends from customising project-specific specifications to delivering premium installation, culminating in an extensive 10-year manufacturer’s warranty that covers both the quality of installation and the render systems applied.
The installation team is skilled and certified in a broad spectrum of exterior finishes, including Monocouche Spray Render, Silicone Thin Coat render, external wall insulation rendering, brick slips, and Cladding remediation.
To further establish trust in our expertise:
- Watch render installation videos on our YouTube channel.
- Visit our Instagram page for recent portfolio work.
- Check out our 5-star customer reviews on Google.
For all your rendering needs, contact us today! We are committed to ensuring your complete satisfaction.
Trust and Worth
Our Clients
External Wall Insulation prices
| Work | Typical price |
|---|---|
| External wall insulation | £130–£190 per m² |
Prices updated 11 July 2026 · Every project is quoted individually after a free survey.
External Wall Insulation — your questions answered
External wall insulation costs £130–£190 per m² including labour and materials, depending on insulation thickness, system choice and access. Grants of up to £15,000 are available for qualifying homes, and the Energy Saving Trust estimates £300–£500 annual heating savings on a semi-detached property.
EWI fixes 60–150mm of insulation board (EPS, mineral wool or phenolic) to the outside of your walls and renders over the top. On a solid-wall home it typically cuts heating bills by 25–40% — the Energy Saving Trust estimates £300–£500 a year on a semi-detached property.
EWI on a semi-detached property takes about two weeks. Thin-coat silicone rendering is typically completed in a week, and monocouche spray render takes just 3–4 days on a semi-detached house thanks to the efficiency of the spray pump.
Usually not — re-rendering in a similar finish falls under permitted development for most houses. You DO need consent if the property is listed, in a conservation area with an Article 4 direction, or a flat. External wall insulation that changes the appearance may also need approval — we advise on this at survey, free of charge.
Where
External Wall Insulation across Surrey, Hampshire & Berkshire
Questions about external wall insulation?
Talk it through with our team — free survey, honest advice, fixed written quote. No pressure.
Next step
Get your free fixed-price quote
Ready to transform your home?
Free survey, fixed written quote, manufacturer-backed system warranties.