Calculate external wall insulation cost
External wall insulation cost by property type
Average £6,000
Average £8,000
Average £17,000
Average £18,000
Average £25,000
Installed cost by insulation system
Average £170 / m²
Average £180 / m²
Average £175 / m²
Average £175 / m²
Worked wall-area examples
What can increase the quote?
- Scaffolding and difficult access.
- Cracks, damp or other wall repairs before insulation.
- Moving gutters, downpipes, cables and external services.
- Window-reveal, sill and roof-edge detailing.
- Premium render or decorative finish.
- Removing existing external wall insulation: current benchmark £30–£40 per m².
Source
External Wall Insulation Cost: 2026 UK Guide
Used for July 2026 property-type, installed-per-m² and insulation-system benchmarks.
Frequently asked questions
How much does external wall insulation cost per square metre in 2026?
Current UK guidance is about £150–£200 per m² installed, with an average around £175 per m². The final rate depends on insulation system, wall condition, access, detailing and finish.
How much is external wall insulation for a semi-detached house?
The current published example is £14,000–£20,000, averaging about £17,000. A real quote can move outside that range if wall repairs, scaffolding or service alterations are substantial.
How much does external wall insulation cost for a detached house?
The current detached-house example is £20,000–£30,000, with an average around £25,000.
What extra costs should I allow for?
Scaffolding, wall repairs, moving rainwater pipes and services, architectural details, removing existing insulation and premium render finishes can all add to the project total.