What is the average cost per m² for a house extension in the UK in 2026?

The average cost per m² for a house extension in the UK in 2026 ranges from £1,600 to £2,200 at standard specification, based on a Midlands baseline. London costs are typically 35% higher, ranging from £2,160 to £2,970 per m².

How much does a loft conversion cost per m² in the UK?

A loft conversion costs between £1,400 and £2,000 per m² at standard specification in the UK Midlands baseline. In London, expect £1,890 to £2,700 per m². These figures exclude VAT and professional fees.

What is the cost per m² for a new build house in the UK?

New build house costs range from £1,800 to £2,800 per m² at standard specification (Midlands baseline). London new builds typically cost £2,430 to £3,780 per m². Figures exclude VAT, professional fees, and land costs.

How do regional multipliers affect UK construction costs?

Regional multipliers reflect the variation in labour costs across the UK. London has the highest multiplier at 1.35×, meaning costs are 35% above the Midlands baseline. The North East has the lowest at 0.88×. These multipliers are applied to base cost-per-m² figures to give region-specific estimates.

Do these costs include VAT?

No. All figures on this page are exclusive of VAT. Most construction work on existing residential properties is subject to 20% VAT. New build residential construction is zero-rated for VAT purposes. Conversions of non-residential buildings to residential use may qualify for the 5% reduced rate. Always confirm VAT treatment with your contractor and accountant.

What professional fees should I add on top?

Professional fees typically add 8–15% to the construction cost, depending on project complexity. This includes: architect or designer (3–8%), structural engineer (1–3%), quantity surveyor or estimator (0.5–2%), planning application fees (£206–£462 for most residential projects), and building regulations fees (£200–£900+ depending on project value). Our construction estimating service starts from £255 and provides a detailed breakdown before you commit to any contractor.

How often is this data updated?

We review and update this benchmark data quarterly, incorporating new project completions, updated material price indices, and changes in regional labour markets. The current data reflects Q2 2026 market conditions. The page was last updated on 19 April 2026. Significant market events (such as material price spikes or major policy changes) may trigger out-of-cycle updates.

Can I use this data in my own reports or publications?

Yes — this data is freely available to cite, share, and reference, provided you attribute it to Page Building Consultants and include a link to this page (build-estimate.com/uk-construction-cost-benchmarks). For commercial licensing or bespoke data requests, please contact us directly.

What is the difference between GIA and NIA?

GIA (Gross Internal Area) is the total floor area measured to the internal face of the external walls, including all internal walls, columns, and circulation space. NIA (Net Internal Area) excludes structural elements, plant rooms, and common areas — it represents the usable floor space. Residential projects typically use GIA; commercial projects often use NIA. The difference is usually 10–20% of total floor area.

Why are London costs so much higher than the rest of the UK?

London construction costs are typically 25–40% above the national average due to several compounding factors: higher skilled labour rates (London weighting), logistics and access constraints (congestion charges, restricted delivery windows, limited site storage), higher preliminaries costs (site welfare, security, scaffolding in dense urban areas), and stronger demand relative to contractor supply. The 1.35× multiplier we use is a conservative average — prime central London projects can run at 1.5× or higher.

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Updated 19 April 2026|Free reference data

UK Construction Cost
Benchmarks 2026

Name: UK Construction Cost Benchmarks 2026
Creator: Page Building Consultants
Published: 2026-01-01
License: https://creativecommons.org/licenses/by/4.0/

Independently compiled cost-per-m² data for 8 project types across all UK regions. Based on live project data from Page Building Consultants — updated quarterly and freely available to cite.

8 project types

12 UK regions

Updated Q2 2026

Live project data

Use the Cost Calculator Jump to Data TablesCite this page: build-estimate.com/uk-construction-cost-benchmarks

Last updated:19 April 2026

Cost-per-m² figures, regional multipliers, trade breakdowns and labour rates reviewed against live project data.

Next review: July 2026 (Q3)

Free data worth sharing — send it to your team or clients.

Cost Per m² by Project Type

National average figures for England. Apply regional multipliers (see table below) to adjust for your location. All costs exclude VAT, professional fees, and planning charges unless stated.

Project Type	Unit	Low	Mid	High	Typical Total
Single Storey Extension	per m² GIA	£1,800	£2,400	£3,200	£36,000 – £128,000
Two Storey Extension	per m² GIA	£1,600	£2,100	£2,800	£64,000 – £224,000
Loft Conversion	per m² GIA	£1,500	£2,000	£2,700	£37,500 – £135,000
New Build House	per m² GIA	£1,900	£2,600	£3,800	£190,000 – £950,000
Full Refurbishment	per m² GIA	£800	£1,400	£2,200	£48,000 – £440,000
Commercial Fit-Out	per m² NIA	£700	£1,200	£2,500	£70,000 – £2,500,000
Groundworks	per m² site area	£120	£280	£600	£24,000 – £1,200,000
Garage Conversion	per m² GIA	£900	£1,300	£1,800	£13,500 – £54,000

All figures are national averages for England, excluding VAT (20%), professional fees (8–15%), and planning/building regulations charges. Costs reflect Q2 2026 market conditions. Click any row to expand detail.

Regional Cost Multipliers

Apply these multipliers to the national average cost-per-m² figures above to get a region-adjusted estimate. Based on BCIS regional indices and live tender data.

Your base cost (£/m²)

£/m²

Adjusted totals update automatically

Region	Multiplier	Adjusted Cost/m²	Notes
London	1.35×	£3,240/m²	Inner London premium; labour scarcity and logistics costs
South East	1.18×	£2,832/m²	Commuter belt; high demand, skilled labour premium
East of England	1.10×	£2,640/m²	Cambridge/Hertfordshire push costs above average
South West	1.05×	£2,520/m²	Broadly national average; coastal areas slightly higher
West Midlands	0.97×	£2,328/m²	Near national average; Birmingham slightly higher
Scotland	0.96×	£2,304/m²	Near average; Highlands add 10–15% for remoteness
East Midlands	0.95×	£2,280/m²	Below average; good contractor availability
North West	0.94×	£2,256/m²	Manchester/Liverpool push regional average up
Yorkshire & Humber	0.92×	£2,208/m²	Competitive market; strong local contractor base
Wales	0.90×	£2,160/m²	Below average; rural areas may add logistics costs
North East	0.88×	£2,112/m²	Lowest regional costs; strong value for money
Northern Ireland	0.85×	£2,040/m²	Lowest UK costs; strong local contractor market

Multipliers are indicative and based on BCIS regional tender price indices and Page Building Consultants live project data. Individual projects may vary. Last updated: 19 April 2026.

Detailed Cost Data

Trade-by-trade breakdowns, current material price indices, and UK labour day rates — all updated Q2 2026.

Trade / Element	% of Total Cost	Notes
Preliminaries & Site Setup	8–15%	Site management, welfare, plant hire, insurance
Substructure & Foundations	8–18%	Higher for poor ground conditions or deep foundations
Superstructure & Frame	12–20%	Masonry, timber frame, or steel depending on type
Roof	8–14%	Pitched roofs higher; flat roofs lower but more maintenance
External Walls & Cladding	6–12%	Render, brick slip, or timber cladding
Windows & External Doors	5–10%	Aluminium bifolds significantly increase this element
Internal Partitions & Joinery	4–8%	Bespoke joinery pushes this higher
Mechanical & Electrical	12–20%	Largest variable; underfloor heating, EV charging add cost
Finishes & Decoration	6–12%	Tiling, flooring, painting — specification-sensitive
Kitchens & Bathrooms	5–15%	Highly specification-dependent; bespoke kitchens vary widely

All rates are indicative UK national averages for Q2 2026. Labour rates exclude employer NI, holiday pay, and plant. Material prices are supply-only ex-VAT. Actual costs will vary by project, location, and contractor.

Frequently Asked Questions

Common questions about how to use and interpret UK construction cost benchmark data.

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These figures are based on live project data from Page Building Consultants, cross-referenced with BCIS (Building Cost Information Service) published indices and RICS guidance notes. They represent typical costs for standard specification projects in England and should be used as a starting point for budget planning, not as a substitute for a professional estimate. Actual costs can vary by ±20–30% depending on site conditions, specification, and contractor selection.

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Cite this page

Page Building Consultants (2026). UK Construction Cost Benchmarks 2026. Retrieved from https://www.build-estimate.com/uk-construction-cost-benchmarks. Last updated: 19 April 2026.

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UK Construction CostBenchmarks 2026