External Wall Insulation & Roughcasting in Trowbridge & Wiltshire
Wiltshire Rendering provides external wall insulation and roughcasting in Trowbridge and across Wiltshire. External wall insulation, commonly known as EWI, can improve the thermal performance of suitable properties while providing an opportunity to renew their exterior finish. We also apply robust roughcast finishes to create a distinctive textured appearance and added weather protection. Every installation is planned around the construction, condition and requirements of the property.
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What Is External Wall Insulation?
External wall insulation is a system installed on the outside of a property. Insulation boards are securely fixed to the external walls before being covered with a reinforced base coat and a protective decorative finish. The system effectively wraps the outside of the building, helping to reduce the amount of heat passing through uninsulated walls.
At Wiltshire Rendering, we assess each property carefully before recommending EWI. The wall construction, existing coatings, exposure, roofline, damp-proof course, windows and other external details all influence how the system should be designed.
External wall insulation is often considered for solid-wall properties that cannot be insulated using conventional cavity wall insulation. It may also suit certain rendered homes where the exterior already requires substantial renewal. The result can combine improved thermal performance with a complete exterior transformation.
Professional EWI Installation in Wiltshire
Cracks are among the most visible signs that a rendered surface requires attention. TheA successful EWI project depends on careful design, correct preparation and close attention to details around openings and adjoining surfaces. The existing walls must be stable and any defects, moisture problems or loose coatings should be addressed before insulation is installed.
The insulation boards are fixed in accordance with the selected system specification. A reinforced base coat and mesh are then applied to provide strength and help manage stresses across the surface. Corners, window reveals and other vulnerable areas are formed using suitable trims and reinforcement.
The installation is completed with a compatible render or textured finish selected for the property. The complete system must work together, so individual components should not be substituted without considering compatibility and manufacturer requirements. Our team follows a structured process to create a secure, even and weather-resistant exterior.y may be caused by age, movement, impact damage, poor preparation, water penetration or a previous application that has failed. Although some cracks remain small, others can gradually widen and allow moisture to enter behind the surface.
Blown render occurs when sections lose their bond with the wall beneath. The affected areas may sound hollow when tapped and can eventually break away from the property. Painting over blown render will not restore that bond, so loose material generally needs to be removed before the damaged area can be rebuilt.
Our render repair work can address cracked surfaces, hollow sections, damaged corners, failed beads, worn reveals, impact damage and localised surface deterioration. When a wall has suffered widespread failure, we can also advise whether partial restoration or complete re-rendering would provide the more dependable long-term result.
Improve Comfort and Exterior Appearance
External wall insulation can help reduce heat loss through suitable walls, allowing a property to retain warmth more effectively. The Energy Saving Trust reports that around one-third of the heat lost from an uninsulated home can escape through its walls. Actual performance and savings will depend on the construction, insulation specification, heating use and condition of the property.
Because the insulation is installed externally, it does not reduce the internal floor area of rooms. The system can also help cover ageing brickwork or tired render, creating a renewed exterior with a wide choice of colours and textures.
EWI can reduce cold internal wall surfaces and may help rooms feel more comfortable, but insulation must form part of a properly considered building approach. Ventilation, existing damp, roof insulation and other parts of the property should also be taken into account.
Why Choose Wiltshire Rendering?
Our team combines exterior rendering experience with a detailed approach to preparation and finishing. We assess the existing walls, discuss the performance and appearance you want to achieve and recommend an appropriate system for the building.
We understand that EWI affects numerous exterior details, not just the main wall surfaces. Window reveals, corners, drainage, service penetrations and rooflines must all be considered if the installation is to look professional and perform effectively.
Throughout the project, we maintain clear communication and work carefully around your property. Our objective is to deliver a well-finished exterior that improves protection, complements the building and meets the agreed system specification.
Get a Free EWI or Roughcasting Quote
Improve the protection, performance and appearance of your property with professional external wall insulation or roughcasting. Contact our experienced team for advice and a free quotation in Trowbridge or anywhere across Wiltshire.
If you are considering external wall insulation or roughcasting in Trowbridge or Wiltshire, our team can assess your property and explain the available options. We provide free, no-obligation quotations based on the size, construction and current condition of the building.
Contact Wiltshire Rendering today to arrange an assessment and discuss the right exterior wall solution for your property.
Frequently Asked Questions
External wall insulation adds a layer of insulating material to the outside of a property. The boards are mechanically and adhesively fixed where appropriate, then covered with a reinforced base coat and compatible decorative finish. This reduces heat transfer through the external walls and helps the building retain warmth. Because the work is completed outside, the internal dimensions of rooms are not reduced. EWI can also transform ageing exterior walls by covering them with a new rendered finish. The system specification must be suited to the wall construction, exposure and fire performance requirements, which is why an assessment and properly designed installation are essential.
EWI is commonly considered for solid-wall homes and properties where cavity wall insulation is not suitable, but an inspection is required before any recommendation can be made. The walls must be structurally sound, and existing problems such as penetrating damp, leaking gutters or defective render should be resolved before insulation is installed. Available space around boundaries, roof overhangs, window reveals and external fixtures must also be considered. Listed buildings, period properties and homes in conservation areas may face additional design or consent requirements. We can assess the exterior and explain whether EWI or an alternative rendering solution would be more appropriate.
A roughcast-style finish may be possible with some external wall insulation systems, but compatibility must be confirmed as part of the specification. EWI is formed from several components designed and tested to work together, including insulation boards, fixings, reinforcement, base coats and the final protective finish. Applying an unsuitable heavy or incompatible coating could affect performance. We will consider the appearance you want and identify a finish that is approved for the selected system. If traditional roughcasting is not appropriate for that EWI installation, we can discuss alternative textured renders that provide a similarly robust and characterful appearance.
Roughcast and pebble dash are related textured rendering techniques, but they are not exactly the same. Roughcast generally contains aggregate mixed into the wet finishing coat before it is applied to the wall. This creates a varied but integrated texture. With traditional pebble dash, dry stones or aggregates are thrown onto a freshly applied backing coat, leaving the individual stones more visible. Both finishes can provide a durable, weather-resistant exterior when correctly applied. The right option will depend on the existing property, the required appearance and whether the finish is being installed over masonry, an existing render system or compatible external wall insulation.
Planning permission may be required when external wall insulation materially changes the appearance of a building. Requirements can be stricter for listed buildings, flats, conservation areas and other designated locations. The Planning Portal recommends consulting the local planning authority where restrictions may apply. Building Regulations can also apply to external wall insulation and extensive re-rendering. Where 25 per cent or more of an external wall is renovated, thermal performance requirements will normally need to be considered. Property owners should confirm the necessary permissions and approvals before work begins, particularly on older, listed or unusually constructed buildings.
We provide external wall insulation and roughcasting in Trowbridge and throughout the wider Wiltshire area. Our coverage includes Melksham, Bradford-on-Avon, Chippenham, Devizes, Westbury, Warminster, Corsham and surrounding towns and villages. We work with homeowners, landlords, developers and commercial property owners, tailoring each exterior wall solution to the building and project requirements. If you are outside these locations, contact our team with your postcode and details of the property. We can confirm availability, discuss whether an initial survey is required and provide a clear quotation based on the proposed work.