Cost per square metre is the most-used benchmark in London renovation budgeting — and the most frequently misunderstood. Understanding what the figure includes, how specification level affects it, and where the per-m² model breaks down is essential for any renovation budget conversation.
The cost-per-square-metre figure for London renovation is cited constantly and understood poorly. Prospective clients ask "what does a renovation cost per square metre?" and receive answers ranging from £800 to £5,000/m² — a range so wide as to be almost meaningless without context. The reason for the range is not evasion; it is that the figure is genuinely dependent on a large number of variables, and a single number without qualification is misleading.
This guide explains what affects the cost per square metre of a London renovation, provides realistic ranges by specification level for 2026, and explains where the per-m² model fails.
What the cost per square metre measures
The cost per square metre of a renovation is typically expressed as a construction cost (contractor cost, excluding professional fees, VAT, and furnishings) divided by the gross internal area (GIA) of the renovated space. It is a useful comparator between projects of similar scope and specification; it is not a reliable absolute predictor for any individual project.
What is typically included in the construction cost: - All trade labour (carpentry, plastering, tiling, electrical, plumbing, decoration) - Materials (structural steel, insulation, plasterboard, flooring, sanitaryware, kitchen cabinetry, paint) - Site preliminaries (hoarding, scaffolding, waste disposal, site management) - Contractor's overheads and profit (typically 15–25%)
What is typically excluded: - Professional fees (architect, structural engineer, project manager): add 12–20% of construction cost - VAT: 20% on most renovation works (some works to Listed Buildings qualify for 5% or 0% VAT) - FF&E (furniture, fixtures, and equipment beyond built-in items): varies enormously - Party Wall surveyor fees - Planning application fees
Specification levels and their cost ranges
Strip-out and basic refurbishment (£800–£1,200/m²)
The minimum level of renovation — new kitchen and bathrooms (at standard specification), redecoration throughout, new flooring, electrical and plumbing updates to comply with current regulations. No structural alterations.
Appropriate for: a buy-to-let investment renovation, a probate property being brought to rentable standard, or a first-time buyer's flat being made habitable.
Typical scope: new white goods kitchen (IKEA or Howdens), standard sanitary ware (Ideal Standard, Bristan taps), LVT or laminate flooring, Dulux Trade paint throughout, new consumer unit and smoke detectors.
What it doesn't include: new structural openings, any extension, bespoke joinery, specialist finishes, or premium materials.
Mid-range renovation (£1,500–£2,500/m²)
A substantive renovation — typically including some structural work (removal of one or two walls), a quality kitchen (Poggenpohl, Bulthaup entry-level, or similar), well-specified bathrooms (Duravit sanitaryware, Hansgrohe taps), engineered timber or quality LVT flooring, some bespoke joinery (fitted wardrobes, alcove shelving), and a quality decorating finish.
Appropriate for: a family home owner-occupier renovation, a mid-market prime London property being upgraded.
Typical scope: 1–2 structural wall removals (steel beams), kitchen at £20,000–£40,000, bathrooms at £8,000–£15,000 each, engineered oak floors, fitted wardrobes, 2-coat premium paint finish.
High specification renovation (£2,500–£4,000/m²)
A full renovation to a luxury residential standard — natural stone floors and bathroom surfaces, bespoke joinery throughout, premium kitchen (Bulthaup, Gaggenau appliances), high-specification M&E (underfloor heating, MVHR, Lutron lighting control), premium decorating (specialist finishes, premium paint brands), and significant structural alterations.
Appropriate for: prime London owner-occupier properties (Kensington, Chelsea, Belgravia, Notting Hill), high-value rental properties targeting the premium market.
Typical scope: natural stone (marble, limestone) in bathrooms and reception floors, bespoke kitchen at £60,000–£120,000, Gaggenau or Miele appliances, underfloor heating throughout, Lutron HomeWorks lighting control, MVHR, bespoke wardrobes and fitted furniture, Farrow & Ball or specialist decorating finish.
Ultra-high specification (£4,000–£7,000+/m²)
The highest tier of London residential renovation — every element at the maximum specification level, including specialist trades (decorative plaster, scagliola, specialist stone laying), custom furniture integrated into the architecture, comprehensive smart home systems, and a level of finish detail that requires highly experienced contractors and extended programmes.
Appropriate for: trophy properties, royal or embassy-standard residences, and projects where the cost-per-m² benchmark is less meaningful than the quality of each individual specification decision.
Typical scope: all of the high specification elements plus specialist decorative plasterwork, book-matched marble throughout, bespoke furniture designed specifically for the spaces, full Crestron or Savant AV integration, bespoke metalwork and hardware, multiple specialist finishes per room.
What distorts the cost per square metre
Wet rooms and kitchens: A kitchen or bathroom costs far more per m² than a bedroom or circulation space. A kitchen of 25 m² at £100,000 costs £4,000/m² for that room alone; a bedroom of 20 m² at £15,000 costs £750/m². The overall project cost per m² depends heavily on how many kitchens and bathrooms are being renovated relative to the total area.
Structural complexity: A project involving basement creation, extensive steelwork, or underpinning has a much higher cost per m² than a project of the same size involving only internal fit-out.
Small projects: The cost per square metre of a small renovation (50 m²) is typically higher than a large renovation (300 m²) at equivalent specification. Fixed costs (preliminaries, mobilisation, professional fees) are spread over fewer square metres. A small London flat renovated at high specification can easily exceed £5,000/m² even without exceptional specification, simply due to scale.
Access and site constraints: A sixth-floor London flat with no goods lift has higher construction costs than an equivalent ground-floor townhouse. All materials and waste must be carried by hand; certain plant cannot be used. Site constraint premiums of 10–20% are common in constrained London locations.
Listed Buildings: Listed Building works are more expensive than standard renovation — specialist materials, specialist trades, conservation-approved methods, and longer programmes all add cost. Listed Building VAT relief (0% on approved alterations) partially offsets this but does not eliminate the premium.
Professional fees and VAT
The total project cost to the client is construction cost plus professional fees plus VAT plus FF&E.
Professional fees: 12–20% of construction cost for a full team (architect, structural engineer, project manager, specialist consultants). For a £500,000 construction project, professional fees of £75,000–£100,000 are normal.
VAT: Standard rate (20%) applies to most renovation works. VAT on the construction cost of a £500,000 project is £100,000. Some works qualify for reduced rate: conversions of non-residential buildings to residential (5%), certain works to buildings unoccupied for 2+ years (5%), and approved alterations to Protected (Listed) Buildings (currently 0% for certain categories under a political transition — confirm with the VAT advisor as rules have changed).
Total project budget: For a high-specification London renovation at £3,000/m² construction cost over 200 m²: - Construction: £600,000 - Professional fees (15%): £90,000 - VAT (20%): £120,000 - FF&E (estimate): £200,000–£400,000 - Total: £1,010,000–£1,210,000
Cost benchmarks by room type (2026, London, high specification)
These are construction costs only (not FF&E), London rates, 2026:
Principal bathroom (8–12 m²): £25,000–£60,000. Natural stone, quality sanitaryware, bespoke vanity, heated towel rail, underfloor heating, full decoration.
En-suite bathroom (5–7 m²): £15,000–£35,000.
Kitchen (20–35 m² including dining): £60,000–£180,000. Bespoke cabinetry, stone worktops, premium appliances, island with services, extraction.
Master bedroom with dressing room (25–35 m²): £20,000–£50,000. Bespoke wardrobes, window treatments, decoration.
Loft conversion (40–60 m² new floor area): £90,000–£180,000 construction including structural, dormer, and internal fit-out.
Single-storey rear extension (20–30 m²): £80,000–£160,000 including structural, glazing, services, and internal fit-out.
Basement creation (50–80 m² new floor area): £200,000–£500,000 depending on existing conditions and specification.
The cost-per-square-metre is a starting point for budgeting, not an answer. The most useful approach is to define the scope, the specification level, and the specific rooms involved — and then to cost each element from first principles, using the benchmarks above as a sanity check rather than a substitute for a properly costed specification.
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