External wall insulation products UK - EWI systems & materials

External wall insulation UK – Professional EWI services

External Wall Insulation (EWI) is one of the most effective ways to improve the energy performance, comfort and appearance of properties across the UK. This service is designed for homes with solid walls or buildings that lose heat through external walls, where traditional cavity insulation is not an option.

We deliver complete external wall insulation solutions, from technical assessment and material selection to professional installation and finishing. The focus is on long term performance, compliance with UK regulations and measurable energy savings, not short term fixes.

What is external wall insulation (EWI)

External Wall Insulation is a system installed on the outside of a building that reduces heat loss through solid walls. Insulation boards are fixed to the external walls and finished with a reinforced render or cladding system that protects the insulation and improves the facade.

Unlike internal insulation, EWI wraps the entire building envelope. This significantly reduces thermal bridges, stabilises indoor temperatures and protects the structure from weather exposure. It is a proven solution widely used in both residential and commercial buildings across the UK.

How EWI works on solid walls

Insulation boards are mechanically fixed and bonded to the external wall
A reinforced base coat protects the insulation and prevents cracking
A decorative render or finish seals the system and improves aesthetics
Heat loss through walls is reduced by up to 45 percent

Benefits of external wall insulation

External wall insulation delivers immediate and long term benefits that go beyond lower energy bills. The system improves both the performance and appearance of the property while increasing its overall value.

From an energy perspective, EWI significantly reduces heat loss, making indoor temperatures more stable throughout the year. Homes stay warmer in winter and cooler in summer, which directly improves living comfort and reduces reliance on heating systems.

Key advantages of EWI

Lower energy bills through improved thermal efficiency
Increased comfort and reduced cold spots inside the property
Enhanced external appearance with modern finishes
Reduced risk of condensation and damp issues
Improved sound insulation in urban areas

Our EWI systems and materials

Choosing the right insulation system is critical for performance, durability and compliance. We offer a range of certified EWI systems suitable for different building types, exposure levels and budgets.

Each system is selected based on thermal requirements, fire performance, moisture resistance and finish options. This ensures the insulation works effectively for decades, not just a few seasons.

Insulation material options

EPS insulation boards for cost effective thermal performance
Mineral wool for enhanced fire resistance and breathability
PIR insulation for high performance solutions with reduced thickness

Render and finish options

Silicone render with high flexibility and dirt resistance
Mineral render for breathable traditional finishes
Acrylic render for colour stability and impact resistance

Who is it suitable for

External wall insulation is particularly suitable for properties with solid brick or stone walls built before the 1930s. It is also used on non traditional constructions and buildings where cavity wall insulation is not possible or insufficient.

Before installation, the property is assessed for wall condition, exposure level and planning considerations. This ensures the system is technically appropriate and compliant with local requirements.

Typical suitable properties

Solid wall houses and older buildings
Homes with high heating costs
Properties undergoing facade renovation
Residential and small commercial buildings

Planning permission is rarely required, but it may apply to listed buildings or properties in conservation areas. We support clients with this process where necessary.

Our external wall insulation installation steps

A detailed on site survey is carried out to assess wall condition, building type and exposure level. Based on this assessment, we select the appropriate insulation system, fixing method and finish to match the technical requirements of the property.

The insulation system is specified according to thermal performance targets, fire safety standards and UK compliance requirements. This stage ensures the correct insulation thickness, materials and render system are selected before installation begins.

External walls are cleaned, repaired and prepared to ensure proper adhesion of insulation boards. Any defects or irregularities are addressed to create a stable and durable base for the EWI system.

Insulation boards are mechanically fixed and bonded to the walls, followed by reinforcement mesh embedded into a base coat. This creates a strong, impact resistant layer that prevents cracking and ensures long term system stability.

A protective render or facade finish is applied to seal the insulation system and enhance the appearance of the property. Clients can choose from a wide range of colours and textures to achieve the desired aesthetic.

The completed installation is inspected to confirm compliance with system specifications and UK Building Regulations. This final step ensures the external wall insulation system meets performance, safety and quality standards.

The result is a seamless external insulation layer that improves energy efficiency, protects the building structure and enhances the appearance of the property for decades.

External wall insulation costs and savings

The cost of external wall insulation depends on several technical and practical factors related to the property and the chosen system. Each building is assessed individually to ensure the insulation delivers long term performance, durability and compliance with UK Building Regulations.

Although external wall insulation requires a higher upfront investment than some basic insulation solutions, it offers measurable savings over time. Reduced heat loss leads to lower energy consumption, improved EPC ratings and increased property value, making EWI a cost effective solution in the long term.

What affects the cost of external wall insulation

Cost factor	Why it matters
Total wall area	Larger wall surfaces require more insulation materials and longer installation time
Building height	Taller properties may require additional scaffolding and safety measures
Insulation material	EPS, mineral wool and PIR differ in price, thermal performance and fire rating
Render or facade finish	Silicone, mineral or acrylic renders vary in durability and cost
Access and site conditions	Limited access or complex layouts can increase installation complexity

Energy savings after installation can be significant, particularly in properties with uninsulated solid walls. Many homeowners notice reduced heating demand within the first heating season, resulting in lower bills and improved indoor comfort throughout the year.