EWI Facades

An EWI facade (External Wall Insulation) is a system that involves applying a layer of insulation material to the exterior walls of a building before covering it with a protective and decorative finish, such as render or brick slips.

EWI facades significantly reduce heat loss, making buildings more energy-efficient whilst also improving their appearance. This proven method is widely used for upgrading the thermal performance of existing buildings and is a preferred choice for achieving high energy efficiency standards in new construction.

EWI System Overview

EWI System Overview An external wall insulation system enhances both the thermal efficiency and appearance of a building. Here’s how it works:

Insulation Board Installation

Insulation boards are adhesively and mechanically fixed to the building’s outer surface. The type and thickness of insulation, adhesive, and fixings are professionally specified based on substrate type, environmental factors, and wind-loading requirements. EWI systems can also be applied onto rail systems, for use on SFS frames or where a drained cavity is required.

Basecoat Application

A specialist mineral or synthetic base coat is applied over the insulation. This polymer-modified coat adds strength and flexibility, with a fabric reinforcing mesh embedded for extra durability. It serves as a weather-resistant barrier and prepares the surface for the final finish.

Finish Application

The system is then ready for the chosen finish, whether it’s a smooth thin coat render, a heavier thick coat, a traditional dry dash, or a brick effect finish. Custom combinations of colours and textures can also be applied for a unique result.

The final product is a thermally efficient, weatherproof, breathable, and low-maintenance facade that complies with modern building and fire regulations. EWI systems typically have a design life of over 30 years.

27+ YEARS EXPERIENCE

EWI Finishes

EWI systems consist of insulation, a reinforcing base coat and a finish of choice. There are many different types of EWI finishes, showcasing the versatility of these systems.

Thin Coat Renders

One of the most popular finishes, thin coat renders, includes silicone, silicate, acrylic and mineral renders. These are typically applied to match the grain size, with thicknesses ranging from 0.6mm to 3mm, though 1.5mm is the most common.

These premixed renders are easy to apply with a trowel and generally only require a single coat. Some may need a primer or additional coatings, especially mineral thin coats. They come in a vast array of colours (often hundreds) and can be customised to match specific project requirements. With the addition of silicone in many of these renders, they are low-maintenance and easy to clean.

Thick Coat Renders

Thick coat renders, usually through colour mineral renders, are mixed with water and applied at a thickness of up to 15mm. These renders can be spray-applied for a heavy, rough texture or hand-scraped for a more refined, scratch-render finish.

However, colour options are more limited, often restricted to whites and pastels due to the pigment concentration. The added thickness enhances impact resistance, making them a durable choice.

Dry Dash

Dry dash remains a traditional and popular finish. Using a thick coat of coloured render as a base, local aggregates (stone chips) are hand-thrown into the wet render. The combination of various coloured base coats and aggregates can create unique visual effects.

Brick Effect

The UK has a long-standing affinity for brick, and there are several ways to replicate a brick finish on an EWI system without constructing an actual brick wall. Some popular options include:

Clay Brick Slips: Brick tiles, which range for 6mm to 15mm thick, are adhesively fixed to the EWI basecoat, with mortar joints created using specialist grouts. This method offers a highly realistic brick finish.

Acrylic Brick Slips: These are flexible, thin imitation brick tiles which make them easy to apply and more cost effective than clay slips. Adhesively fixed to the EWI basecoat, the joints are replicated with specialist grouts.

Brick Effect Render: This technique uses a base coat in the colour of the mortar joints, followed by a second coat in the brick colour. The render is then textured and cut back to reveal the ‘mortar,’ creating the illusion of brickwork. Additional effects can be achieved using paint or resin stains.

Benefits of EWI Facades

Improved Energy Efficiency

EWI significantly reduces heat loss by adding a continuous layer of insulation, leading to more stable indoor temperatures. This results in lower energy bills by reducing the need for heating in winter and cooling in summer.

Reduced Carbon footprint

Enhanced energy efficiency leads to lower carbon emissions, supporting sustainability goals and helping meet stricter energy regulations.

Improves Building Appearance

EWI systems offer a variety of finishes, from smooth renders to textured coatings and brick effects. This allows for a modernised appearance while improving the building’s overall performance.

Weather Protection

EWI provides an additional layer of defence against the elements, such as rain, wind, and UV rays. This extends the building’s lifespan by reducing weather-related wear and tear.

Increased Property Value

A building equipped with an EWI system is more appealing to buyers and tenants, thanks to its enhanced aesthetics, improved thermal comfort, and lower energy costs.

Sound Insulation

EWI systems also offer noise reduction by adding an extra barrier, which is especially beneficial in urban areas.

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