Build It magazine’s cost guide puts a typical self-build at £2,500–£3,000 per m² with a main contractor, and a plain design you manage yourself can come in nearer £2,200. On a 100–150 m² family home that means roughly £220,000–£450,000 for construction alone. Construction is only part of the answer to ‘how much does it cost to build a house in the UK?’ Fees, connections and a contingency add about a quarter again, and the plot comes on top.
What affects the cost per m² of a new house
Who runs the job matters most. Hiring each trade yourself and buying from a builders’ merchant is the cheap end, paid for in your own time and in the risk that one late trade holds up the next. A main contractor adds overheads and profit for taking on one point of responsibility, and a turnkey firm usually charges more again for fixing the price early. Wide glazing, bespoke joinery and a designer kitchen add up quickly, and Build It reckons that building to Passivhaus rather than the Building Regulations minimum costs around 20% more. Region matters less than people expect: the same guide adds only 2–5% for the South East, South West and Scotland, though BCIS notes that London is often dearer. Two storeys also beat a bungalow on cost per m², since a single roof and set of foundations serve twice the floor area. Then there is the ground. A slope, a high water table or shrinkable clay near trees can turn simple strip footings into deep trench fill or piles.
How much does it cost to build a 3 bedroom house in the UK?
Take a detached three-bedroom house of 120 m² on two storeys, on reasonable ground outside London, with the owner running a team of subcontractors. At £2,200–£2,800 per m² the build line comes to £264,000–£336,000. Design, a structural engineer, surveys, planning, building control and a structural warranty might add £25,000–£45,000 between them; that band is my own allowance, not a published figure. Water, sewer, power and broadband connections run to £10,000–£25,000 in most self-build guides, and a 10% contingency on the build is another £26,000–£34,000. That puts the total at roughly £325,000–£440,000 before the plot. Land is left out on purpose, because plot prices vary too much by area to average. A 4 bedroom house of 150 m² priced the same way has a build line of £330,000–£420,000. Here is how that build line might split, rounded and for illustration only:
- Groundworks, drainage and foundations: £25,000–£40,000, more on clay or a slope
- Shell (walls, floors, stairs and roof): £105,000–£115,000
- Windows, external doors and rooflights: £20,000–£26,000
- Plumbing, heating and electrics, first and second fix: £45,000–£60,000
- Plastering, joinery, flooring and decoration: £45,000–£55,000
- Kitchen and bathrooms: £25,000–£40,000, the line that moves most with taste
What the per m² figure leaves out
The plot, first, and it rarely comes alone. In England and Northern Ireland a bare plot where building has not started is normally charged Stamp Duty Land Tax at non-residential rates, with nothing due on the first £150,000. Scotland and Wales have their own land taxes, and conveyancing and a land survey sit on top. Planning itself is cheap. The Planning Portal fee table puts a full application for one new house in England at a few hundred pounds, yet pre-application advice, discharging conditions and the ecology or tree reports behind them soon add up. Building control fees vary between councils and registered approvers. A ten-year structural warranty is a premium of its own, on top of building control. Ask for utility quotes early; they can be slow. Where your council charges the Community Infrastructure Levy, it is worked out per square metre of new floor space; budget for it until a self-build exemption is confirmed in writing.
Do you pay VAT when you build your own home?
Very little, if the paperwork is right. A VAT-registered builder putting up a new dwelling zero-rates the construction and the building materials it fits. Any trade you pay direct for work on the new house should also invoice at 0%, and a bill showing the standard rate needs querying before you pay it. Professional services are different. Architects, surveyors and other consultants always charge the standard rate, and so does the hire of plant, scaffolding or site fencing on its own. If you build a house from scratch and buy materials yourself, you pay VAT at the counter and reclaim it later through HMRC’s refund scheme for DIY housebuilders, online or on form VAT431NB. There is one claim only. For homes completed from 5 December 2023 onwards it must go in within six months of completion, with VAT invoices, the planning permission, plans and evidence of completion. Carpets, most appliances, tools and fitted furniture other than the kitchen do not qualify.
How to keep a self-build budget under control
Put the six lines from the split above into a spreadsheet with three columns: the estimate, the quote that replaces it and what you actually paid. Hold a 10–15% contingency in a separate account and treat it as spent. On clay or a sloping plot I would keep the top end. When a quote comes in over its line, look for the saving inside that line first, a plainer tile or a simpler staircase, before you touch the contingency; kitchen and bathrooms usually have the most room. Most overspends grow out of the decisions that most often go wrong on a self-build, not out of the rates. For your own number, take the floor area from the drawings, multiply it by both ends of the per m² range, then add fees, connections, contingency and the plot one line at a time. As you work through the stages of building a house, from plot to completion, replace each estimate with a firm quote. By the time the groundworker is booked, the range should have closed to a figure you can show a lender.
