External wall insulation
A warmer house, wrapped from the outside.
Solid-wall houses lose heat fast. External wall insulation fixes that from the outside, so you keep every inch of room inside and get a new rendered finish on top.
Stock imageOverview
Most houses built before the 1930s have solid brick walls with no cavity to fill. In winter the heat walks straight through them. External wall insulation (EWI) puts a continuous layer of insulation board around the outside of the building, then seals it in with a reinforced basecoat and a decorative render finish.
Because the work happens outside, you can stay in your home the whole time. No re-plastering, no moving radiators, no losing floor space. And when the scaffold comes down, the house looks brand new.
Warmer rooms, fewer draughts
A continuous wrap stops the cold spots and condensation you get around solid walls.
Lower heating bills
Insulating solid walls is one of the biggest single savings you can make on an older home.
Nothing lost inside
All the work is external, so rooms, sockets and skirting stay exactly where they are.
A complete facelift
Finished in silicone or acrylic render in the colour and grain you choose.
Stock imageThe spec
What's involved.
- Typical build-up
- Adhesive, 90–110mm insulation board, fixings, mesh-reinforced basecoat, primer, topcoat
- Board options
- EPS (expanded polystyrene) or mineral wool where fire rules require it
- Finish
- Silicone or acrylic thin-coat render, 1.0–2.0mm grain
- Best for
- Solid-wall houses, hard-to-treat cavities, tired or cracked existing render
- Time on site
- Usually 2–4 weeks for a typical semi, weather permitting
How we do it
- 01Survey and moisture check
- 02Strip-back and preparation
- 03Boards bonded and pinned
- 04Mesh and basecoat
- 05Primer and topcoat
- 06Details, beads and clean-up
Inside a warm wall
Seven layers between your brick and the weather.
Tap a layer to see what it does.
Savings estimator
How much heat could you keep in?
A rough guide based on typical solid-wall houses. Your survey gives the real numbers.
Based on typical published figures for insulating solid walls, scaled by house type and your annual heating spend. Indicative only.
Questions
About external wall insulation.
Will I need planning permission?
Often not, but it depends on the house and where you live. Conservation areas and listed buildings have extra rules. We'll flag it at survey and point you in the right direction.
What happens to window sills and downpipes?
Sills are usually extended to clear the new wall thickness, and pipes, lights and satellite dishes are taken off and refitted on brackets. It's all included in the quote.
Is there funding available?
Government and energy-company schemes come and go. Ask us at survey and we'll tell you what's currently worth looking at for your house.
Free survey · Fixed written price
Want a price for external wall insulation?
Book a free, no-pressure survey. We'll look at your walls, talk through the options and send a clear written price.