Local costs · South West · September 2026
How much does an extension cost in Bristol?
A mid-range 25 m² single-storey extension in Bristol costs about £65,500 to £81,000 including VAT, or £2,600 to £3,200 per m² at South West prices. Bristol charges £735 for building control on a 10 to 40 m² extension (full plans, including VAT): the 22nd cheapest of the 91 councils we checked, 12% below the typical council (£840). With design, a structural engineer, building control and a 15% contingency, budget £81,000 to £105,000.
Work out your project in Bristol
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Typical prices in Bristol
| Project | Building work | Budget to plan for |
|---|---|---|
| Single-storey extension, 25 m² | £65,500 to £81,000 | £81,000 to £105,000 |
| Double-storey extension, 40 m² | £95,000 to £120,000 | £116,000 to £152,000 |
| Dormer loft conversion, 30 m² | £58,500 to £72,500 | £72,500 to £93,000 |
| Kitchen, medium | £9,200 to £16,300 | £10,600 to £18,800 |
| Bathroom refit | £6,100 to £9,200 | £7,100 to £10,600 |
Building prices in South West run about 4% above the UK average outside London. Kitchens and bathrooms vary less from place to place than extensions and lofts.
Building control fees in Bristol
| Work | Charge |
|---|---|
| Extension up to 10 m² (full plans) | £735 |
| Extension 10 to 40 m² (full plans) | £735 |
| Larger extension, 40-80 m² (full plans) | £895 |
| Extension 10 to 40 m² (building notice) | £700 |
| Loft conversion up to 40 m² | £735 |
| Garage conversion | Not published |
Bristol charges £735 for building control on a 10 to 40 m² extension (full plans, including VAT): the 22nd cheapest of the 91 councils we checked, 12% below the typical council (£840). Source: Bristol's building control charges, 1 April 2026. Plan + inspection, inc VAT totals.
Private approved inspectors set their own prices and are often competitive, so it is worth asking one or two for a quote as well. See how Bristol compares with every council we checked.
Notes on Bristol's schedule
Own schedule. Single band up to 40 m2; next band 40-80 m2. No garage-conversion line.
Planning
If your extension needs planning permission, a householder application in England costs £548. Many single-storey rear extensions are permitted development and need no application, and a lawful development certificate (£274) confirms it.
Other councils in South West
Building control for a 10 to 40 m² extension:
- Bath and North East Somerset: £696
- Wiltshire: £755
- Exeter: £800
- Mid Devon: £896
- North Devon: £896
- Plymouth: £973
- South Hams: £1,095
- Teignbridge: £1,095
- West Devon: £1,095
- Cornwall: £1,140
Questions people ask
How much does an extension cost in Bristol?
A mid-range 25 m² single-storey extension in Bristol costs about £65,500 to £81,000 including VAT for the building work, or £2,600 to £3,200 per m², based on South West prices reviewed in September 2026. With fees and a 15% contingency, budget £81,000 to £105,000.
How much is building control in Bristol?
Bristol charges £735 (including VAT) for a 10 to 40 m² extension (full plans), according to its published schedule (1 April 2026).
How much does a loft conversion cost in Bristol?
A mid-range 30 m² dormer loft conversion in Bristol costs about £58,500 to £72,500 including VAT for the building work, and about £72,500 to £93,000 with fees and a 15% contingency.
Before you get quotes
- How to compare builders' quotes line by line
- Plan your whole budget, including the costs people forget
- Trades: price an extension element by element with editable unit rates