External Wall Insulation (EWI) is one of the most effective ways to improve the energy efficiency of solid wall properties across Manchester. It works by adding a continuous layer of insulation to the outside of your home, creating a protective thermal barrier that significantly reduces heat loss and improves year-round comfort.
Reduce heat loss through solid walls by 40-50%. Save £400-£700 per year on heating bills.
EWI acts as a render — refresh tired brickwork, add a modern finish, and choose your colour. Silicone, acrylic, or mineral renders available.
Work happens outside — no furniture moving, no room size reduction, no need to redecorate.
Eligible households may receive full or partial support through ECO4, subject to property assessment, supplier funding, scheme availability and final approval. Eligibility does not guarantee funding, and a customer contribution may be required.
EWI significantly improves EPC rating — typically from E/D to C/B.
EWI is ideal for older solid wall properties, especially Victorian and Edwardian homes common across Manchester. It is the best solution when cavity wall insulation is not possible or existing walls are poorly performing.
EWI is ideal for pre-1920s homes that typically feature solid brick or stone walls. These properties are common in Manchester’s Victorian and Edwardian housing stock, especially in terraced streets. Since they have no cavity to fill, external insulation provides a highly effective way to improve energy efficiency and reduce heat loss.
It is also suitable for homes with no existing insulation or where the current external render is damaged, outdated, or in need of a complete aesthetic upgrade.
EWI is generally not required for cavity wall properties, as cavity wall insulation is usually a more cost-effective and less disruptive solution in those cases.
It may also be unsuitable or require special permission for listed buildings, where external alterations are restricted due to heritage protection rules. Similarly, homes located within conservation areas may face design constraints regarding materials, finishes, and external appearance.
Properties with very limited access around the building (typically less than 600mm clearance from boundaries) can also present installation challenges, as sufficient working space is required to properly install the insulation system and apply finishing layers safely and effectively.
The External Wall Insulation (EWI) system is a layered building solution designed to improve thermal efficiency, weather protection, and external appearance of solid wall properties. It works by adding a continuous insulation layer to the outside of the building, reducing heat loss and thermal bridging.
Wall Preparation & Adhesive Application
The system starts with an adhesive layer, usually a flexible cementitious or PU adhesive, which bonds the insulation securely to a properly prepared wall surface. This ensures stability and long-term performance.
Insulation Board Installation (EPS / Mineral Wool / Phenolic)
Next is the insulation layer, typically EPS, mineral wool, or phenolic boards ranging from 80–120mm in thickness depending on performance requirements. These boards are fixed using both adhesive and mechanical fixings for added strength and wind resistance.
Mechanical Fixings for Structural Security
Mechanical fixings (disc anchors) are installed at around 4–8 per square metre to secure the system and maintain uniform pressure across the surface.
Reinforced Base Coat with Mesh Layer
A reinforced base coat is then applied, embedded with alkali-resistant fibreglass mesh. This layer strengthens the system, prevents cracking, and provides a solid base for the finish.
Primer Coat for Surface Preparation
After this, a primer coat is applied to ensure proper adhesion and even absorption of the final layer.
Final Render Finish (Silicone / Acrylic / Mineral)
The system is completed with a finish render—usually silicone, acrylic, or mineral—applied at 1.5–3mm thickness. This outer layer protects against weather, allows breathability, and gives the building its final decorative appearance.
Component and Specification:
We use a range of high-performance insulation materials selected based on property type, available wall space, thermal targets, and budget requirements. Each material is designed to improve energy efficiency, reduce heat loss, and enhance overall comfort while meeting UK building standards.
EPS insulation boards typically range from 80–120mm in thickness and achieve a U-value of approximately 0.18–0.22 W/m²K. This is one of the most cost-effective insulation solutions and is widely used in residential retrofit projects. It offers reliable thermal performance, moisture resistance, and durability, making it suitable for most standard wall insulation applications.
Mineral wool insulation is also commonly installed in 80–120mm thickness and provides a similar U-value range of 0.18–0.22 W/m²K. In addition to thermal efficiency, it offers excellent soundproofing and high fire resistance, making it ideal for properties where acoustic comfort and safety are important considerations. It is also breathable, helping to manage moisture within wall systems.
Phenolic boards are a high-performance insulation option, typically installed at 60–100mm thickness, achieving superior U-values of around 0.13–0.16 W/m²K. This makes it one of the most thermally efficient materials available. It is particularly suitable for properties with limited wall space where maximum insulation performance is required with minimal thickness.
External Wall Insulation (EWI) requires precise detailing to ensure thermal performance, weather protection, and long-term durability. Proper installation is not just about adding insulation—it must integrate seamlessly with the building’s existing structure to avoid moisture issues and thermal bridging.
EWI systems typically add 100–150mm of thickness to external walls, which can affect roof detailing. To ensure proper weather protection, roof eaves may need to be extended so that rainwater is directed away from the insulated walls.
Window and door reveals are one of the most important areas in EWI design. If left untreated, they can become weak points for heat loss. We install insulated reveal boards, typically using PIR insulation between 25–50mm thick, to reduce thermal bridging. Compression seals are also used to ensure airtightness and improve energy efficiency around openings, helping maintain consistent indoor temperatures.
At ground level, the insulation system is carefully finished to prevent moisture rising from the ground affecting the building. EWI systems are typically terminated 150–200mm above ground level using a bellcast bead detail.
Stop beads are installed at key junctions such as windows, doors, corners, and roof lines to create a clean and durable finish. These components protect the edges of the insulation system, prevent cracking, and ensure a neat architectural appearance.
We assess wall construction, roof eaves, windows, ground levels, and access. Check for planning permission or conservation area restrictions.
We specify insulation thickness, finish (silicone, acrylic, mineral), and detail all junctions. Handle planning permission if needed.
We assess wall construction, roof eaves, windows, ground levels, and access. Check for planning permission or conservation area restrictions.
The cost of External Wall Insulation (EWI) in Manchester depends on the size, type, and condition of the property, as well as the insulation system selected. However, many homeowners are eligible for government-backed ECO4 funding, which can significantly reduce or fully cover installation costs.
Terraced house (typical in Levenshulme, Burnage): £8,000-£12,000 — ECO4 grant upto 100% — Your cost £0 if eligible
Semi-detached (typical in Stockport, Oldham): £10,000-£15,000 — ECO4 grant upto 100% — Your cost £0 if eligible
Detached (typical in Bramhall, Didsbury, Hale): £12,000-£20,000 — ECO4 grant upto 100% — Your cost £0 if eligible
| Property Type | Typical Areas in Manchester | Estimated Cost | ECO4 Grant Support | Final Cost (If Eligible) |
|---|---|---|---|---|
| Terraced House | Levenshulme, Burnage | £8,000 – £12,000 | Up to 100% funded | £0 |
| Semi-Detached | Stockport, Oldham | £10,000 – £15,000 | Up to 100% funded | £0 |
| Detached House | Bramhall, Didsbury, Hale | £12,000 – £20,000 | Up to 100% funded | £0 |
Choosing Compliant Retrofits means working with a team that prioritises quality, compliance, and long-term performance in every External Wall Insulation (EWI) project. We focus on delivering systems that are not only energy-efficient but also fully aligned with UK building standards and retrofit best practices.
We are experienced installers of approved EWI systems, working with BBA-certified materials and trusted manufacturers to ensure durability, safety, and performance.
We assess your eligibility for ECO4 funding, guide you through the application process, and handle the necessary documentation to make the journey simple and stress-free.
Every junction matters. We carefully design and install eaves, window reveals, and wall junctions to minimise thermal bridging and maximise energy efficiency throughout the property.
Choose from silicone, acrylic, or mineral render systems, allowing you to match performance requirements with your preferred aesthetic style and breathability needs.
Choose from silicone, acrylic, or mineral render systems, allowing you to match performance requirements with your preferred aesthetic style and breathability needs.
From initial consultation and technical survey to installation and final sign-off, we manage the entire process with clear communication and professional oversight.
We provide a no-obligation assessment to help you understand your property’s suitability, potential energy savings, and available funding options before you commit.
A: 2-4 weeks depending on property size and complexity. Scaffolding erected week 1, installation week 2-3, finish render week 3-4.
A: Usually permitted development, but listed buildings and conservation areas (e.g., parts of Didsbury, Chorlton, Hale) may require permission. We advise on your specific property.
Yes. We offer a range of colours and finishes including silicone (self-cleaning), acrylic (durable), and mineral (breathable).
A: No. EWI includes breathable renders and proper detailing at ground level, windows, and roof to prevent damp. It can actually reduce condensation by warming external walls
A: Yes, if you receive qualifying benefits or meet ECO4 Flex criteria. Contact us for a free eligibility check.
