Construction costs in the UK have risen significantly over the past few years, driven by material price inflation, labour shortages, and supply chain disruption. Understanding what building work actually costs — and why — is essential for anyone planning a construction or renovation project. This guide provides current indicative costs for common building works.
Important Caveats
All the figures in this guide are indicative only. Actual costs depend on:
Always obtain at least three competitive tenders and, for larger projects, instruct a quantity surveyor to produce a cost plan before approaching the market.
House Extensions
Single-storey rear extension:
A typical 20m² single-storey extension costs £30,000–£70,000 including structural works, foundations, finishes, and services connections, but excluding VAT and professional fees.
Double-storey extension:
A double-storey extension is often more cost-effective per square metre than a single-storey, as you're spreading the cost of foundations and roof over more floor area.
Loft Conversions
Basic loft conversion (rooflight/Velux): £25,000–£45,000
Dormer loft conversion: £35,000–£60,000
Hip-to-gable conversion: £40,000–£65,000
Mansard conversion: £50,000–£80,000
These figures are for a typical three-bedroom semi-detached house in Yorkshire. London costs are typically 25–40% higher.
Kitchen Extensions and Fit-Outs
Kitchen fit-out only (no structural works):
Open-plan kitchen-diner extension:
Garage Conversions
A straightforward garage conversion (insulation, damp-proof membrane, plasterboard, electrics, heating, window) typically costs £8,000–£20,000, making it one of the most cost-effective ways to add living space.
New Build Residential
Shell and core only (not finished): £1,200–£1,800/m²
Turnkey residential (fully finished): £2,000–£3,500/m²
A 100m² three-bedroom house built to a good but not premium specification typically costs £200,000–£350,000 in build costs alone — excluding land, professional fees, planning costs, and VAT.
Commercial Construction
Industrial/warehouse: £600–£1,100/m²
Office fit-out: £500–£1,500/m² (depending on specification)
Retail fit-out: £400–£1,200/m²
Renovation and Refurbishment
Full renovation of a standard terraced house: £30,000–£80,000 (excluding major structural works)
Full rewire: £3,000–£6,000
Full replumb: £4,000–£9,000
New bathroom (fit-out only): £4,000–£12,000
New boiler and heating system: £2,500–£5,500
Professional Fees
Don't forget to budget for professional fees on top of construction costs:
On a £200,000 project, professional fees can add £15,000–£30,000.
How to Control Costs
1. Appoint a quantity surveyor at design stage, before the project is committed
2. Get competitive tenders — don't accept the first quote
3. Agree a fixed-price contract with appropriate provisions for variations
4. Manage change orders carefully — changes during construction are expensive
5. Build in contingency (10–15% for refurbishment, 7–10% for new build)
Volarex provides quantity surveying services for projects of all sizes across Yorkshire, Greater Manchester, and the wider UK. Contact us to discuss cost planning and procurement for your project.