Average Building Costs Per Sq M For 2025 – A UK Guide

When planning a construction project, understanding the average building costs per square metre will help you create a realistic budget and avoid nasty surprises. 

Whether you’re building a home, extending your property, or adding a garage, this guide breaks down the average costs per square metre. 

In addition, this guide not only explores average costs by region—including East Anglia, London, the Midlands, and more—but also provides a breakdown of expenses by project stage and room type.

Building Costs Per Square Metre In The UK

In terms of build specification, our pricing calculator has three options:

• Low spec is a basic finish; e.g. Leyland, Everest, Wickes.

• Standard spec is a standard finish; e.g. Dulux, Hamilton, Slim Line.

• Premium spec is a high-spec finish; e.g. Farrow & Ball, Fine Line, Siemens.

For the purposes of this comparison of build costs per square metre, we have reviewed the costs for standard specification. In addition, for each specification, we’ve provided a range of prices to reflect the varying types of contractors:

• Low benchmark – smaller companies are generally lower cost but less specialised and with low project management function; good for low/mid-spec projects and tight budgets.

• Mid benchmark – medium-sized companies offer a balanced mix of cost-effectiveness and specialisation; good for mid-range projects for effective execution within moderate budgets.

• High benchmark – larger companies generally have a higher cost base but can handle a wide variety of specialist tasks; good for mid/high-spec projects and project management.

How Much Does It Cost To Build A 3-Bedroom House Per Square Metre?

When calculating the cost of building a three-bedroom detached house, we made the following assumptions:

• The average number of bedrooms in the UK is 2.95, so we rounded up to 3. 

• The floorplan is based on the average UK dwelling size of 94m2.

The rooms included in are three bedrooms, a bathroom, a kitchen, a living room, a dining room, a cloakroom, the hallway and landing, and a dedicated boiler and storage cupboard. 

Here’s a table showing the average costs of building a 3-bed house for a standard-spec project in the UK:

3-Bedroom Detached House (Standard)	Total Average Build Cost	Average Cost Per Sq Metre
	Low Benchmark	Mid Benchmark	High Benchmark	Low Benchmark	Mid Benchmark	High Benchmark
East Anglia	£279,511	£304,922	£330,332	£2,974	£3,244	£3,514
London	£295,524	£331,321	£367,252	£3,144	£3,525	£3,907
Midlands	£271,386	£296,057	£320,729	£2,887	£3,150	£3,412
North England	£264,604	£288,659	£297,852	£2,815	£3,071	£3,169
Northern Ireland	£273,124	£297,338	£322,115	£2,900	£3,163	£3,427
Scotland	£273,689	£298,570	£323,451	£2,912	£3,176	£3,441
South East	£294,138	£328,900	£360,987	£3,129	£3,499	£3,840
South West	£273,800	£316,240	£347,093	£3,009	£3,364	£3,692
Wales	£264,783	£296,075	£318,053	£2,817	£3,150	£3,384
Average	£276,729	£306,454	£331,985	£2,954	£3,260	£3,532

All costs exclude VAT.

Here’s what the data shows for the cost of building a 3-bed house to a standard spec:

• It costs 12% more to build a 3-bed house in London than in other regions.

• The minimum cost is £264,604, and the maximum cost is £367,252.

• The total average cost is £305,056, or £3,249 per square metre.

Housebuilding Cost Breakdown By Project Stage – London

Here’s an example of the associated costs for the different stages of building a house for a standard-spec project – when using a mid-benchmark contractor in London:

Total	£331,321	100.0%
External wall structure and lining	£60,145	18.2%
Foundations and substructure	£37,234	11.2%
Roof structure and coverings	£36,555	11.0%
Floor structure and lining	£20,156	6.1%
Preliminaries	£19,875	6.0%
External windows and doors	£18,718	5.6%
Units, worktops and kitchen appliances	£15,815	4.8%
Floor preparation and finishes	£14,097	4.3%
Steel and structural supports	£13,713	4.1%
Decoration	£13,183	4.0%
Internal wall structure and lining	£12,487	3.8%
Heating and cooling	£11,905	3.6%
Wall preparation and finishes	£10,167	3.1%
Wired appliances	£10,033	3.0%
Drainage and pipework	£8,757	2.6%
Plumbed appliances	£7,751	2.3%
Internal doors and frames	£5,133	1.5%
Ceiling structure and lining	£3,979	1.2%
Wiring and fuseboards	£2,887	0.9%
Stairs, balustrades and lifts	£2,822	0.9%
Ceiling preparation and finishes	£1,780	0.5%
Joinery	£1,588	0.5%
Fixtures and fittings	£1,279	0.4%
Demolitions	£1,263	0.4%

Cost Breakdown By Room – London

Here’s a breakdown of the associated costs by room for a standard-spec house build – when using a mid-benchmark contractor in London:

Total	£331,321	100%
G | Ground Floor	£116,657	35.2%
I | First Floor	£61,567	18.6%
Kitchen	£37,960	11.5%
R | Pitched roof	£36,555	11.0%
Bathroom	£13,501	4.1%
En-suite	£11,345	3.4%
Living room / family room	£8,473	2.6%
Bedroom 1	£8,258	2.5%
WC	£7,847	2.4%
Boot Room / Cloakroom	£7,198	2.2%
Bedroom 2	£7,198	2.2%
Bedroom 3	£6,976	2.1%
Landing incl. stairs	£4,366	1.3%
Boiler Cupboard	£3,418	1.0%

How Much Does It Cost To Build A Ground-Floor Extension Per Square Metre?

In our calculations, the costs of building an extension are based on the following:

• The roof of the extension is pitched, not flat.

• The extension is constructed out of brick/block, not a timber frame.

• A 20m² single-storey rear extension, including dining room, utility room, WC.

Which rooms you choose ultimately affects the overall cost of the extension. 

Here’s a table showing the average costs of building a ground-floor extension for a standard-spec project in the UK:

Single-Storey Rear Extension	Total Average Build Cost	Average Cost Per Sq Metre
	Low Benchmark	Mid Benchmark	High Benchmark	Low Benchmark	Mid Benchmark	High Benchmark
East Anglia	£79,067	£86,255	£93,443	£2,636	£2,875	£3,115
London	£83,258	£93,492	£103,834	£2,775	£3,116	£3,461
Midlands	£76,740	£83,716	£90,693	£2,558	£2,791	£3,023
North England	£74,934	£81,746	£88,558	£2,498	£2,725	£2,952
Northern Ireland	£77,293	£84,275	£91,298	£2,575	£2,809	£3,043
Scotland	£77,334	£84,364	£91,395	£2,578	£2,812	£3,046
South East	£83,142	£92,968	£102,038	£2,771	£3,099	£3,401
South West	£77,518	£89,564	£98,302	£2,670	£2,985	£3,277
Wales	£74,938	£83,795	£89,986	£2,498	£2,793	£3,000
Average	£78,247	£86,686	£94,394	£2,618	£2,890	£3,146

All costs exclude VAT.

Here’s what the data shows for the cost of building a 3-bed house to a standard spec:

• It costs 9% more to build an extension in London than in other regions.

• The minimum cost is £74,934, and the maximum cost is £103,834.

• The total average cost is £86,443, or £2,885 per square metre.

How Much Does It Cost To Build A Garage Per Square Metre?

The cost comparisons assume the garage is an extension to an existing dwelling, not a new detached structure. These cost excludes the installation of appliances and EV chargers. It’s based on a single garage with a pitched roof, comprising a gross external area of 16.5m2.

Here’s a table showing the average costs of building a single garage for a standard-spec project in the UK:

Single Garage With Pitched Roof	Total Average Build Cost	Average Cost Per Sq Metre
	Low Benchmark	Mid Benchmark	High Benchmark	Low Benchmark	Mid Benchmark	High Benchmark
East Anglia	£41,399	£45,163	£48,927	£2,509	£2,737	£2,965
Greater London	£43,858	£49,041	£54,502	£2,658	£2,972	£3,303
Inner London	£44,837	£50,017	£54,799	£2,717	£3,031	£3,321
Midlands	£40,239	£43,898	£47,556	£2,439	£2,660	£2,882
North England	£39,233	£42,800	£46,367	£2,378	£2,594	£2,810
Northern Ireland	£39,568	£43,082	£46,673	£2,393	£2,611	£2,829
Scotland	£39,644	£43,248	£46,851	£2,403	£2,621	£2,839
South East	£43,495	£48,635	£53,380	£2,636	£2,948	£3,235
South West	£40,587	£47,114	£51,711	£2,554	£2,855	£3,134
Wales	£39,040	£43,654	£46,910	£2,366	£2,646	£2,843
Average	£41,190	£45,665	£49,767	£2,505	£2,768	£3,016

All costs exclude VAT.

Here’s what the data shows for the cost of building a single garage with a pitched roof to a standard spec:

• The minimum cost is £39,040, and the maximum cost is £54,799.

• The total average cost is £45,451, or £2,763 per square metre.

Average Building Costs Per Square Metre In 2025

So, how much does it cost to build in the UK? Based on the three different construction projects covered in this article, you can expect building to cost on average (when using a mid-benchmark contractor):

• 3-bedroom house: £306,454, or £3,260 per square metre.

• Ground-floor extension: £86,686, or £2,890 per square metre.

• Single garage with pitched roof: £46,665, or £2,768 per square metre.

Please remember that these costs do not include VAT, and there may be other additional costs, such as obtaining planning permission, conducting structural surveys, making unexpected repairs, and completing custom finishes.

Start your free trial with BuildPartner today to get the most accurate estimate of your construction project.

FAQs About Housebuilding Costs In The UK

Here are some frequently asked questions about housebuilding costs in the UK.

How are housebuilding costs typically split between materials and labour?

Based on a standard-spec 3-bedroom newbuild in London, the typical split of costs would be £90,908 for building materials (27.4%), £79,026 for finishing materials (23.9%), and £161,385 for labour (48.7%), excluding VAT. This breakdown assumes a total construction cost of £331,319.