UK Planning & Building Costs — Complete Guide
Accurate, up-to-date cost guides for common home improvements in the UK. All figures include labour and materials, and are based on 2026 market rates. Use our calculators for a personalised estimate.
What Affects the Cost of a Home Improvement Project?
Location
London and the South East typically cost 20–40% more than the Midlands or North of England.
Size and complexity
Larger projects are cheaper per square metre due to fixed costs, but more expensive overall.
Specification
Bifold doors, underfloor heating, and premium materials add significantly to cost.
Site conditions
Ground conditions, access, and existing services all affect the groundworks cost.
Contractor
Rates vary enormously — always get at least 3 quotes from recommended builders.
VAT
Most construction work is subject to 20% VAT on labour and materials. Planning fees have no VAT.
Cost Guides
Single-Storey Extension Cost
£1,500–£3,000 per m²
Loft Conversion Cost
£1,200–£2,500 per m²
Conservatory Cost
£500–£2,000 per m²
Garage Conversion Cost
Planning Application Fees
Double-Storey Extension Cost
£1,800–£2,800 per m²
Basement Conversion Cost
Porch Cost
Garden Room Cost
Side Return Extension Cost
£1,600–£2,400 per m²
Rear Extension Cost
£1,500–£2,500 per m²
Wrap-Around Extension Cost
£1,800–£2,800 per m²
New Build House Cost
£1,500–£3,000 per m²
Building Regulations Fees
Architect Fees
Structural Engineer Fees
Party Wall Surveyor Fees
Planning Consultant Fees
Demolition Cost
Landscaping Cost
Get a Personalised Estimate
Use our extension cost calculator to get a cost range tailored to your project size, type, and location.