Independent UK planning guide
Single-storey extension costs in the UK
Add ground-floor space with foundations, structure, weatherproofing, services and internal finishes.
Get site-specific quotesTypical UK range
£2,200–£3,500/m²
Straightforward jobs
From £40,000
Typical site time
3–6 months
Build the allowance
How to read this price
Starting allowance
For a straightforward, accessible job with a standard specification.
From £40,000
Typical UK project
An early planning range before a tradesperson inspects the property.
£2,200–£3,500/m²
Likely programme
Site time varies with preparation, sequencing, approvals and drying periods.
3–6 months
These figures are early UK planning allowances. They are not a substitute for an itemised quotation after inspection.
Control the variables
What can change the quote?
Ground conditions and foundations
Steelwork and structural openings
Access, scaffolding and waste
Glazing, services and room specification
Before accepting a quote
Ask for these details in writing
- ✓Labour, materials and VAT
- ✓Preparation and protection
- ✓Access equipment and waste
- ✓Named provisional allowances
- ✓Testing and certification
- ✓Programme and payment stages
- ✓Making good and decoration
- ✓Warranty and snagging process