September 24, 2026
Turnkey House Building Costs and Process
Once you have decided a turnkey route is right for you, two questions remain: what it costs, and what happens between signing and getting the keys. Both answers vary by project, but the structure of both is consistent enough to plan around. This guide sets out what a turnkey house in the UK typically costs, what should be inside that price, and the stages the build runs through.
What does a turnkey house cost in the UK?
For 2026, UK build costs for a new home generally fall between £1,800 and £3,500 per square metre for the construction work, before land, and the range is driven by specification and site conditions rather than floor area alone.
A turnkey price should sit at the upper end of what a comparable shell only price would be, because it covers more. What it should not do is sit meaningfully above the sum of the parts. If a turnkey quote is well above what the same scope would cost assembled separately, ask what the difference is buying you.
One cost trap catches self builders more than any other: the Community Infrastructure Levy. Self build projects can usually claim a full exemption, but only if the correct forms are submitted and acknowledged before development commences. Miss that window and the exemption is lost, regardless of how genuine the project is, so it is worth confirming this has been handled before groundworks start rather than after.
What should be included in a turnkey price?
This is where quotes diverge most, and where comparing headline numbers goes wrong. A complete turnkey price should cover five areas.
| Area | What it covers |
|---|---|
| Design and consent | Architectural drawings, planning application and fees, structural engineering, building control submission and sign off |
| Structure | Groundworks, foundations, drainage, superstructure and weathertight envelope |
| Services | Electrics, plumbing, heating and any renewables |
| Finishes | Kitchen and bathrooms to an agreed allowance, flooring, internal joinery and decoration |
| Completion | Utility connections, snagging and handover |
Our quotes are fixed price and include professional fees and VAT unless the design or specification changes. External works and landscaping vary by project and should be confirmed either way rather than assumed.
What is the turnkey build process, stage by stage?
The programme runs in a set order, because each stage depends on the one before it. It falls into three phases.
Before anything happens on site. It starts with the brief, which is about how you want to live in the house rather than the room count, then design options worked through with the architect against your budget. The planning application follows, typically eight to twelve weeks from submission to decision. Technical design and the building regulations submission run alongside that, and building regulations approval is a separate process from planning rather than part of it. Procurement begins here too, with long lead items ordered well before they are needed.
The build. Groundworks come first, covering excavation, drainage and substructure to damp proof course level, then the superstructure takes the walls and roof through to weathertight. First fix follows, covering electrics, plumbing, heating and the airtightness detailing that has to be right before anything is covered over. Second fix brings plastering, joinery, the kitchen, bathrooms, flooring and decoration.
Completion. External works, the final building control inspection, snagging and handover.
How long does a turnkey house take?
Design and build projects typically run six to eighteen months from first consultation to completion, based on current Cognitive Construction project timescales and subject to planning and site survey.
Two things move that figure most. Planning is the first, and it is largely outside anyone’s control once submitted. Procurement lead times are the second, and they are manageable if handled early. On our Claremont Avenue project the windows and doors carried a lead time of around twenty weeks, which we absorbed by ordering against measured survey checks well in advance rather than waiting until the openings were formed. Handled late, the same item would have stopped the programme dead.
What makes a turnkey price go up during a build?
Very little, if the scope was properly defined at the start. The genuine causes are:
Design or specification changes. If you change your mind on the kitchen or move a wall, the price moves with it. Agreed and priced before the work happens, never after.
Ground conditions. The one genuine unknown until the ground is opened. At Lillingstone Lovell, a clay site with flood risk needed a deep interception drain, upslope soakaways and sub floor pumps. A proper site investigation before quoting reduces this risk substantially but never removes it entirely.
Planning conditions. Occasionally a consent arrives with conditions attached that change the specification.
Outside those, our fixed price holds. No hidden costs, no surprises at the end.
What to do next
- Set your total budget including plot, fees and contingency before designing anything.
- Get ground conditions investigated on your plot before committing to a price.
- Ask for a written scope, not just a number, and compare quotes on that basis.
- Map your lender’s release stages against the builder’s payment stages.
Cognitive Construction delivers turnkey coordinated bespoke builds and design and build projects across Buckinghamshire, Bedfordshire and Northamptonshire, with our trades on our own payroll. We are a vetted member of the Federation of Master Builders, assessed independently on workmanship, customer service and financial standing. See our accreditations and case studies.
FAQs
Contact us today so we can speak with you further about your project.