Full house renovation cost, London 2026: the budget, and how to keep it

Renovating a whole London house in 2026 costs between £850 and £1,950 per square metre. Where you land inside that band turns on three variables: the amount of structural work needed, how much of the wiring and plumbing must be replaced, and the finish level you pick. On those rates a one-bed flat runs about £40,000–£105,000, a three-bed terrace about £95,000–£230,000, and a five-bed detached house £260,000–£640,000. The figure matters less than keeping it fixed once you've set it — so this guide gives you the budget, shows how it splits, and explains how the price holds from quote to handover.

What "full renovation" means here

There's no industry definition, which is exactly why quotes for the "same" job vary so much. In this guide a full renovation means every room taken back to a sound but unfinished shell, the wiring and plumbing renewed or upgraded throughout, any structural changes carried out, and a complete finishes package — kitchen, bathrooms, flooring, tiling and decoration — taken to completion.

It does not cover an extension or a loft conversion. If you're adding floor area as well, budget that as its own project and add it on top. A lighter job — new kitchen, new bathroom, repaint — is a different category that costs far less; the band above is for the full strip-back-and-rebuild.

What it costs by house size

Use these as planning brackets for London in 2026, then narrow them at a survey:

| Property | Floor area | Typical 2026 cost | |---|---|---| | 1-bed flat | 45–55 m² | £40,000–£105,000 | | 2-bed flat | 65–80 m² | £60,000–£150,000 | | 3-bed terrace | 85–115 m² | £95,000–£230,000 | | 4-bed Victorian semi | 130–160 m² | £135,000–£310,000 | | 5-bed detached | 200–300 m²+ | £260,000–£640,000 |

The spread inside each row is real, not hedging. A sound 1960s house with serviceable services sits near the bottom; a period property needing new joists, a rewire, a replumb and heritage-matched finishes sits near the top.

Where the budget actually goes (a percentage split)

Rather than list trades in isolation, it helps to see the budget as proportions, because that's how you spot a quote that's weighted wrong. On a typical mid-spec three-bed London renovation, the split runs roughly:

• Structural work (openings, steels, any chimney-breast removal): 8–18%
• Services — full rewire and replumb, heating, ventilation: 18–28%
• Fabric — insulation, boarding, plaster, screed, floor prep: 12–18%
• Finishes — kitchen, bathrooms, flooring, tiling, decoration, joinery: 35–50%
• Fees, surveys, Building Control and contingency: the balance

Finishes carry the widest swing because that's where your choices live: a stock kitchen and a fully bespoke one can differ by £40,000 on their own. If a quote is light on the services slice, treat it as a warning — the wiring and plumbing are invisible in the finished house, which is why they're the first things a corner-cutting price quietly thins.

The services layer — do it once, properly

The blunt truth on a full renovation: if the house still has its original wiring, or galvanised-steel or lead pipework, you rewire and replumb completely while the walls are open. Redoing electrics or plumbing after plastering and decorating costs several times more per run than doing it first. As a guide for a three-bed terrace: a full rewire is around £5,500–£9,000, a full replumb £7,000–£14,000, and a boiler swap from about £2,200. Gas work has to be done by a registered engineer, not "someone handy with boilers."

Underfloor heating, if you want it, runs roughly £80–£130 per m² in screed and means losing 75–90 mm of floor height across the ground floor — a real consideration in a period home with original floor levels to respect.

The unknowns — and the contingency rule

The cost you can't see from a floor plan is what's behind the plaster and under the boards. In London's period stock, opening up reliably turns up at least one of: damp where a slate damp-course or the pointing has failed, rotten or undersized joists, asbestos in pre-2000 materials, or wiring in worse shape than scoped.

So set a contingency, and ring-fence it. For a London project past the £100,000 mark, hold 15–20% back specifically for the things nobody can price before the walls are open — not for changing your mind on tiles. A refurbishment asbestos survey (£300–£700) and proper damp treatment (£1,500–£6,000 done correctly, not skimmed over) belong in the plan from day one, not as mid-job surprises.

How the price stays fixed

A whole-house budget only holds if two things are true. First, the scope is pinned down before any tool comes out — the kitchen, the appliances, the worktops, the bathroom suites and the flooring all chosen and costed up front, because mid-build changes are where prices run away. Second, every variation after that is written down and signed off before it's actioned, with a price attached.

That's how we work it. You get a quote broken out to trade level, so you can see what each part costs and challenge any line. The start and finish dates go in writing. If something genuinely unforeseen appears once we're in — and on period homes it sometimes does — you see the cost and agree it before we proceed, never after. One project manager holds the whole programme so there's a single person accountable for the number.

The sequence that protects the budget

The single most expensive mistake on a renovation is doing things out of order and then redoing them, so the order of works is itself a cost control. Strip-out comes first, then any structural work — steels and new openings — so the bones are settled before anything covers them. Next comes first-fix: the wiring, the plumbing, the underfloor-heating loops, while the walls are still open and a cable run costs a fraction of what it does later. Only then do the fabric trades go in — insulation, boarding and plaster — followed by screed and floor preparation.

With the shell finished, second-fix services follow (sockets, switches, radiators, sanitary connections), then the finishes proper: tiling, flooring and decoration. The final fit — fittings, kitchen units, sanitaryware, internal doors and joinery — lands last, and snagging closes it out. Skip or reorder any of the early stages to save a week and you buy rework. And because Part A for structure, Part G for hot water and bathrooms, Part L for energy and Part P for electrics are all in play on a whole-house job, each needs Building Control sign-off; without the completion paperwork, selling the house later gets difficult.

Can you live in it while it's done?

Honest answer, by property type:

• A one- or two-bed flat: realistically no. Once the only bathroom and the kitchen are out, there's no habitable space — plan to be out for the 6–14 weeks of the main phase.
• A three-bed house: sometimes, in part, by finishing top-down and keeping one bathroom and a bedroom live as you move down. It adds 15–25% to the programme and a little cost, but saves rent. It has to be planned from the start, not improvised.
• A four- or five-bed: more workable, because a second bathroom can stay in service.

Our straight advice: if you can afford to move out for the noisy 8–16 weeks of the services-and-fabric phase, do. Living on a working site is harder than most people expect, and a short let for that window is usually money well spent.

How long it takes

Counting on-site weeks from first strip-out to final snag, and assuming materials are ordered before the start, the programme scales with the property:

• A five-bed detached house, full bespoke scope: 28–40 weeks
• A four-bed period semi taken back to the brick: 22–32 weeks
• A three-bed terrace that includes structural work: 16–24 weeks
• A one-bed flat: 8–14 weeks

A well-run job comes with a procurement schedule four to six weeks before site start, so nothing holds up the trades once they're in.

Closing CTA

A whole-house renovation can't be priced off a floor plan — the only accurate way is a survey, ideally with a look behind the plaster at the suspect spots. PrimeCraft Surface Solutions surveys, prices to trade level, fixes the dates in writing, and runs the whole job through one project manager across London and the surrounding Home Counties. Book a free site visit, or use the online estimator to get a first ballpark.