Renovation Cost Per Square Metre in London 2026
Cost per square metre is one of the most widely used — and most widely misunderstood — tools in construction budgeting. It provides a useful starting point, but the range for any project type is so wide that the figure needs significant context to be useful. Here's how to use it sensibly.
Why Cost Per Square Metre Varies So Much
The cost per square metre of any renovation or construction project is driven by: the specification level (standard versus high-end finishes and materials); the complexity of the work (structural alterations versus cosmetic fit-out); the proportions of high-cost versus lower-cost elements (bathrooms and kitchens cost far more per square metre than circulation space); the extent of M&E work (a full rewire and replumbing is expensive; patch repairs are not); and London labour rates (which are significantly higher than the national average).
For any given project type, the difference between a budget specification and a high-end specification can easily double the cost per square metre. This is why a figure quoted without context is almost meaningless.
Indicative Ranges for London 2026
Full house refurbishment (standard specification, all trades, excluding kitchen and bathroom supply): £750–£1,200 per m² of total floor area.
Full house refurbishment (mid-to-high specification, including M&E upgrade, full replastering, quality finishes): £1,200–£2,000 per m².
Single-storey rear extension (build cost only, excluding kitchen): £2,500–£4,000 per m² of new floor area. Extensions cost more per m² than refurbishment because they include all structural and external envelope cost in the same floor area calculation.
Loft conversion (standard, one bedroom and shower room): £2,500–£4,500 per m² of converted floor area.
Basement conversion (new basement or conversion of existing void): £4,000–£7,000+ per m². Basement works are the most expensive per m² of any residential project type, reflecting the cost of waterproofing, underpinning, structural design, and complex temporary works.
Kitchen refurbishment only (labour and installation, client-supplied kitchen): £600–£1,500 per m² of kitchen floor area.
Bathroom refurbishment only (full strip and refit, client-supplied sanitaryware and tiles): £1,500–£4,000 per m² of bathroom floor area.
How to Use These Figures
Use cost per square metre to check whether an early budget is in the right zone — not to set a precise cost. If a contractor quotes you significantly below the lower end of the range, ask what has been excluded. If significantly above the upper end, ask what is driving the premium.
To get a figure you can actually rely on for your specific project, you need a scope of works and a properly structured estimate — not a rate-per-square-metre multiplication.
RCB provides structured estimates — not per-square-metre guesses — based on your specific project information, scope, and specification level.
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