EWI Specialist LTD

External wall insulation and rendering across London and Hertfordshire

EWI Specialist LTD is a Hertfordshire-based insulation company working on external wall insulation (EWI) and external rendering for residential properties. The company presents itself as a local, family-run business and states that it has more than 21 years of experience in these two specialisms. Its stated coverage combines Hertfordshire and London, and the site lists specific service areas including Hatfield, Welwyn Garden City, Watford, St Albans, Hemel Hempstead, Harrow and Luton.

The firm describes its installers as fully insured and frames its offer around protecting brickwork, reducing heat loss and renewing the appearance of the façade in a single project. It also states that it is TrustMark registered and works to PAS 2030:2023.

Two core services: insulation systems and render finishes

The service range is organised around two main lines. The first is external wall insulation, presented as an eco-friendly system intended to improve the thermal efficiency of the property. The second is rendering of outside walls, carried out by the company's rendering contractors to give the exterior a new finish.

Within these lines, the material and finish options mentioned are:

• Insulation boards in EPS, Rockwool or Kingspan, including graphite EPS and Kingspan K5 in specific projects.
• Render finishes in silicone, scratch render, brick-effect and pebble dash.
• Brick slip cladding using Licata and Eurobrick products.
• Breathable external wall insulation combined with lime render.

The company also handles render-only work, such as an overlay project of 250 m² in West Byfleet, and mentions additional works on fascias, soffits and gutters in the context of customer feedback.

How a project is structured

The site describes a four-stage process. It begins with a free survey and written quote after a home visit and wall measurements. The customer then chooses the insulation material and render colour, with the company managing the specification and the associated paperwork. Installation is carried out by the company's own insured team, which it says protects the garden and cleans up daily. The final step is a joint inspection of the finished work and the handover of warranty documents.

For pricing, the company offers a cost calculator that produces a per-square-metre estimate and a downloadable quote, and it also offers a customised price guide broken down by project, covering EPS, Rockwool or Kingspan insulation paired with the chosen finish.

Warranty periods

Warranty cover depends on the type of project. For private projects the company states a workmanship warranty of up to 10 years, while qualifying council and funded schemes can reach up to 25 years. On private work, the supplier or material warranty and the company's own workmanship warranty are described as running concurrently.

Projects and areas of activity

The portfolio shown on the site includes external wall insulation in Dagenham, Stanmore (HA7) with 90 mm EPS, West Hanningfield (CM2) with 90 mm graphite EPS, Mill Hill (NW7) with 100 mm Kingspan K5, Hemel Hempstead and Edgware, as well as breathable insulation with lime render in Ealing. A transformation example is also presented for a home in Chelmsford.

Reputation as presented by the company

The company refers to a 4.9-star Google rating and displays a set of Google reviews on its site. The reviews shown highlight same-day contact and same-week site visits, earlier-than-expected start dates, communication with the team and the office, and completion on schedule. Several reviewers mention work on solid masonry or solid walls and describe the finish and the tidiness of the team favourably. These are individual customer accounts reproduced by the company, not an independent assessment.