Ewi Specialist Ltd

EWI Specialist Ltd is an Essex-based team delivering external wall insulation and high-quality render finishes across London and the South East. Founded by Sebastian & Sebastian, we bring over 21 years' hands-on experience. We survey, design and install manufacturer-approved EWI systems that cut heat loss, improve comfort and lift kerb appeal, installed to spec and built to last.

As the work grew, so did our team, backed by solid technical know-how, ongoing training and industry accreditations. Our aim is straightforward: make homes warmer, safer and better looking with external wall insulation and quality rendering. We keep things simple: clear communication, meticulous detail and installations carried out exactly to manufacturer's system specifications and regulations.

That's how we achieve durable, defect-free results that stand the test of time. We proudly offer a guarantee of up to 25 years on our rendering and insulating services, with an insurance-backed guarantee for up to 25 years, giving you long-term comfort and peace of mind. Our services include a cost calculator for instant per-m² estimates and downloadable quotes, offering EPS, Rockwool, or Kingspan insulation with chosen finishes like silicone, scratch, brick-effect, or pebble dash.

We also provide professional energy-saving insights and direct grant guidance.