Local costs · South East · September 2026
How much does an extension cost in Winchester?
A mid-range 25 m² single-storey extension in Winchester costs about £73,000 to £89,500 including VAT, or £2,900 to £3,600 per m² at South East prices. Winchester publishes only building notice charges: £1,085 for a 10 to 40 m² extension (including VAT). With a building notice no plans are approved before work starts. It doesn’t publish a full plans total, so the budget uses the typical full plans charge of the councils we checked. With a measured survey, building regulations drawings, a structural engineer, a typical building control charge and a 15% contingency, plan for £88,500 to £113,000.
Work out your project in Winchester
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Typical prices in Winchester
| Project | Building work | Budget to plan for |
|---|---|---|
| Single-storey extension, 25 m² | £73,000 to £89,500 | £88,500 to £113,000 |
| Double-storey extension, 40 m² | £105,000 to £132,000 | £126,000 to £164,000 |
| Dormer loft conversion, 30 m² | £54,000 to £66,500 | £66,500 to £86,000 |
| Kitchen, medium | £9,700 to £17,200 | £11,100 to £19,800 |
| Bathroom refit | £6,500 to £9,800 | £7,500 to £11,300 |
Building prices in the South East run about 15% above the UK average outside London. Kitchens and bathrooms vary less from place to place than extensions and lofts.
Building control fees in Winchester
| Work | Charge |
|---|---|
| Extension up to 10 m² (full plans) | Not published |
| Extension 10 to 40 m² (full plans) | Not published |
| Larger extension, over 40 m² (full plans) | Not published |
| Extension 10 to 40 m² (building notice) | £1,085 |
| Loft conversion up to 40 m² | £1,020 |
| Garage conversion | £615 |
Winchester publishes only building notice charges: £1,085 for a 10 to 40 m² extension (including VAT). With a building notice no plans are approved before work starts. It doesn’t publish a full plans total, so the budget uses the typical full plans charge of the councils we checked. Source: Winchester’s building control charges. Schedule date: 2026/27. The charges include VAT.
Check before relying on it: the council publishes building notice charges only, so the budget uses the typical full plans range.
Private building control firms (registered building control approvers) set their own prices and are often competitive, so it is worth asking one or two for a quote as well. See how Winchester compares with every council we checked.
Notes on Winchester’s schedule
Winchester publishes only its building notice charges. For full plans it asks for a £250 deposit and invoices the rest, without stating the total. The loft figure (with a dormer; £885 without) and the garage figure are building notice charges too.
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 in writing.
Other councils in the South East
Building control for a 10 to 40 m² extension:
- Milton Keynes: £840
- Horsham: £858
- Crawley: £858
- Folkestone and Hythe: £941.64
- Hart: £960
- Rushmoor: £960
- Windsor and Maidenhead: £990
- Maidstone: £1,023
- West Berkshire: £1,055
- Wokingham: £1,055
- Oxford: £1,125
- Runnymede: £1,182
- Waverley: £1,280
Questions people ask
How much does an extension cost in Winchester?
A mid-range 25 m² single-storey extension in Winchester costs about £73,000 to £89,500 including VAT for the building work, or £2,900 to £3,600 per m², based on South East prices reviewed in September 2026. With a measured survey, design, a structural engineer, a typical building control charge and a 15% contingency, plan for £88,500 to £113,000.
How much is building control in Winchester?
Winchester publishes only building notice charges: £1,085 (including VAT) for a 10 to 40 m² extension. Schedule date: 2026/27.
How much does a loft conversion cost in Winchester?
A mid-range 30 m² dormer loft conversion in Winchester costs about £54,000 to £66,500 including VAT for the building work, and about £66,500 to £86,000 with fees, a typical building control charge 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
- When quotes arrive, check each one against the typical range for your area
Work in Winchester? Firm listings on Estiquote’s map of checked local firms open soon: see what you’ll need. Listing will be free while we build the map, with at least 30 days’ notice before any charge.