Local costs · North East · September 2026
How much does an extension cost in Darlington?
A mid-range 25 m² single-storey extension in Darlington costs about £55,500 to £68,500 including VAT, or £2,200 to £2,700 per m² at North East prices. Darlington charges £710 for building control on a 10 to 40 m² extension (full plans, including VAT): the 17th cheapest of the 91 councils we checked, 15% below the typical council (£840), though its published schedule is older or undated. With design, a structural engineer, building control and a 15% contingency, budget £69,500 to £90,500.
Work out your project in Darlington
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Typical prices in Darlington
| Project | Building work | Budget to plan for |
|---|---|---|
| Single-storey extension, 25 m² | £55,500 to £68,500 | £69,500 to £90,500 |
| Double-storey extension, 40 m² | £80,500 to £101,000 | £99,500 to £131,000 |
| Dormer loft conversion, 30 m² | £49,500 to £61,000 | £62,500 to £80,000 |
| Kitchen, medium | £8,500 to £15,000 | £9,700 to £17,300 |
| Bathroom refit | £5,600 to £8,400 | £6,400 to £9,600 |
Building prices in North East run about 12% below the UK average outside London. Kitchens and bathrooms vary less from place to place than extensions and lofts.
Building control fees in Darlington
| Work | Charge |
|---|---|
| Extension up to 10 m² (full plans) | £490 |
| Extension 10 to 40 m² (full plans) | £710 |
| Larger extension, 40-100 m² (full plans) | £890 |
| Extension 10 to 40 m² (building notice) | £710 |
| Loft conversion up to 40 m² | £800 |
| Garage conversion | £350 |
Darlington charges £710 for building control on a 10 to 40 m² extension (full plans, including VAT): the 17th cheapest of the 91 councils we checked, 15% below the typical council (£840), though its published schedule is older or undated. Source: Darlington's building control charges, 1 November 2024. Inc VAT ("All charges are inclusive of Vat").
Check before relying on it: the schedule is older than 2025 or undated, so check it is still current.
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 Darlington compares with every council we checked.
Notes on Darlington's schedule
Own leaflet. Loft figure is with dormer (without 725).
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 North East
Building control for a 10 to 40 m² extension:
- Stockton-on-Tees: £697
- Durham: £743
- Northumberland: £780
- Sunderland: £840
- Newcastle upon Tyne: £918
- Gateshead: £965
- South Tyneside: £970
Questions people ask
How much does an extension cost in Darlington?
A mid-range 25 m² single-storey extension in Darlington costs about £55,500 to £68,500 including VAT for the building work, or £2,200 to £2,700 per m², based on North East prices reviewed in September 2026. With fees and a 15% contingency, budget £69,500 to £90,500.
How much is building control in Darlington?
Darlington charges £710 (including VAT) for a 10 to 40 m² extension (full plans), according to its published schedule (1 November 2024).
How much does a loft conversion cost in Darlington?
A mid-range 30 m² dormer loft conversion in Darlington costs about £49,500 to £61,000 including VAT for the building work, and about £62,500 to £80,000 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