Group E · New build, extension and structural wall systems
ICF (insulated concrete formwork)
Interlocking EPS blocks filled with concrete on site — structure and insulation in one.
Typical price
ICF (insulated concrete formwork)
£130–£200 per m²
ICF walls (structure and insulation)
Discuss your projectBefore grants · updated 11 October 2026 · a survey confirms the final figure.
- Best for
- Extensions, basements, new homes, self-build
- Guarantee or standard
- System certificate; NHBC/LABC acceptance
- Time on site
- Set by the build programme — agreed with you and your designer.
- Typical price
- £130–£200 per m²
What it is
What is ICF?
Interlocking EPS blocks filled with concrete on site — structure and insulation in one.
Best for: Extensions, basements, new homes, self-build.
Build-up
ICF wall
- 1Internal finish
- 2EPS formwork, inner face
- 3Concrete core — the structure
- 4EPS formwork, outer face
- 5Render or cladding
Who it suits
Which homes is ICF suitable for?
Is my home suitable?
Pick your property type for a straight answer on ICF.
Guidance only — every home is different, and a survey confirms what suits yours.
Houses
- Detached house
- Semi-detached house
- End-of-terrace
- Mid-terrace
- Townhouse
- Mews house and cottage
- Detached bungalow
- Semi and terraced bungalow
- Chalet and dormer bungalow
- Period home
- 1930s home
- Post-war and ex-council house
- Non-traditional / system-built
- Listed building or conservation area
- Farmhouse, barn conversion or rural home
- New build or self-build
Flats and blocks of flats
Commercial and public buildings
Usually suitable Depends — a survey confirms
Not usually suitable for 6 property types
- Park and mobile home — Park and mobile homes need specialist systems, which we arrange through a partner rather than standard measures.
- Converted flat — New-build systems are for new buildings and extensions, not a retrofit for an existing flat.
- Purpose-built flat — New-build systems are for new buildings and extensions, not a retrofit for an existing flat.
- Ground-floor, top-floor flat or maisonette — New-build systems are for new buildings and extensions, not a retrofit for an existing flat.
- Mansion block — New-build systems are for new buildings and extensions, not a retrofit for an existing flat.
- Ex-local-authority flat or maisonette — New-build systems are for new buildings and extensions, not a retrofit for an existing flat.
Materials and brands
What we use
Interlocking EPS blocks filled with concrete on site: structure and insulation in one; very airtight, fast to build (e.g. Nudura, Beco Wallform, Logix).
Heat, bills and EPC
What it does for your heat loss, bills and EPC
In a new build the walls, roof and floor are designed together to meet Building Regulations Part L, and the SAP calculation shows the result before you build. Better airtightness and fewer thermal bridges mean lower running costs from day one, and a strong EPC on completion.
See the EPC points and savings for your home in the EPC plannerU-value before and after, typical heat and bill saving, and EPC points — worked out for your property.Price
How much does ICF cost?
| Service | Typical range, installed |
|---|---|
| ICF walls (structure and insulation) | £130–£200 per m² |
Indicative ranges for London and the South East, supplied and installed, including VAT. Updated 11 October 2026. A survey confirms your final price.
VAT on this work
Insulation installed in homes in Great Britain is zero-rated for VAT until 31 March 2027. Other parts of a job like this — such as a new roof covering, structural work or waterproofing — may be standard-rated. Your quote shows the split.What to expect
Time on site, disruption and approvals
Time on site
Set by the build programme — agreed with you and your designer.
Disruption
Part of a new build or extension project rather than work in an occupied home.
Planning and building control
Planning and building control for the project, design-stage SAP calculations, and the system's certificate (with warranty provider acceptance where relevant).
Guarantee and standard
System certificate; NHBC/LABC acceptance. The guarantee and certification for your job are confirmed in writing in your quote.
Questions
ICF (insulated concrete formwork): your questions answered
How much does ICF cost?
Typically £130–£200 per m² for icf walls (structure and insulation), installed in London and the South East, including VAT and before any grant. Prices updated 11 October 2026. A survey confirms your final figure.
What is ICF?
Insulated concrete formwork: interlocking EPS blocks are stacked on site and filled with concrete. The concrete is the structure, and the EPS stays in place as insulation.
Why build with ICF?
Structure and insulation go up in one step, the walls are very airtight, and it's fast to build — popular for basements, extensions and self-builds.
Is ICF accepted by warranty providers?
ICF systems carry system certificates; acceptance by NHBC or LABC Warranty depends on the system, which we confirm at design stage.
Group E
More in new build, extension and structural wall systems
SIPs (structural insulated panels)
Factory-made insulated panels for walls and roofs.
Timber frame with insulation
Closed-panel timber frame with mineral wool or wood-fibre and an airtight membrane.
Cavity wall new build
Full-fill mineral wool batts or partial-fill PIR in new masonry cavities.
Thermal blocks
Aircrete or insulated blocks for the inner leaf.
Passivhaus and low-energy build
Thermal-bridge-free detailing, airtightness and MVHR for very low energy homes.
Begin your project
Ready to talk about ICF?
Tell us about your home and we'll arrange a survey, then a fixed written quote — no obligation.