Calculate your external wall insulation cost
External wall insulation cost per m² in London
External wall insulation by property type in London
The UK figures are current property examples; the city column applies the same moderated 18% regional weighting as the live calculator.
UK £5,000–£7,000 · avg £6,000£5,250–£7,350 · avg £6,300
UK £6,000–£10,000 · avg £8,000£6,300–£10,500 · avg £8,400
UK £14,000–£20,000 · avg £17,000£14,700–£21,000 · avg £17,850
UK £15,000–£21,000 · avg £18,000£15,750–£22,050 · avg £18,900
UK £20,000–£30,000 · avg £25,000£21,000–£31,500 · avg £26,250
Current UK system benchmarks
What can change a real London quote?
- External wall area
- EPS, mineral wool or board system
- Render or cladding finish
- Scaffolding
- Gutter and pipework changes
- Existing wall condition
Local planning considerations
Dense access, parking, deliveries and contractor overheads can widen the spread between quotations, so use the figures as an early budget rather than a quote.
- Allow separately for parking, loading, permits or restricted delivery windows where a property has difficult street access.
- Flats and managed buildings can add landlord, freeholder or building-management requirements that are outside a basic works estimate.
- Party-wall, structural and access costs should be checked independently on extensions, lofts and major internal alterations.
How the regional model works
The live external-wall-insulation calculator uses only 18% of the broad London regional difference because insulation boards, fixings and render systems contain a substantial nationally priced material component. The resulting London EWI factor is 1.050× and is applied to the current £150–£200 per m² installed benchmark.
Sources
External Wall Insulation Cost: 2026 UK Guide
Published / checked: July 2026
Used for: Installed external-wall insulation cost-per-m² and property-type ranges
Frequently asked questions
How much does external wall insulation cost in London in 2026?
The current UK installed benchmark is £150–£200 per m², averaging about £175 per m². Using the same moderated regional factor as the live calculator gives a London planning rate of about £158–£210 per m².
How much is external wall insulation for a semi-detached house in London?
The current UK semi-detached example is £14,000–£20,000, averaging £17,000. Applying the moderated London model gives about £14,700–£21,000, with a modelled midpoint near £17,850.
Why is the London EWI adjustment smaller than the broad regional factor?
External wall insulation contains a large material and system component, so the live calculator applies only 18% of the broad regional difference rather than treating the entire installed price as locally variable labour.
What can make external wall insulation more expensive?
Wall repairs, scaffolding, architectural detailing, moving rainwater pipes and services, premium finishes, difficult access and larger exposed wall areas can all increase the final quote.