Estiquote

Local costs · South East · September 2026

How much does an extension cost in Runnymede?

A mid-range 25 m² single-storey extension in Runnymede costs about £72,500 to £89,500 including VAT, or £2,900 to £3,600 per m² at South East prices. Runnymede charges £1,182 for building control on a 10 to 40 m² extension (full plans, including VAT): the 6th dearest of the 91 councils we checked, 41% above the typical council (£840). With design, a structural engineer, building control and a 15% contingency, budget £89,500 to £115,000.

By Estiquote · Prices reviewed · Council fees from Runnymede's published schedule · How we calculate

Work out your project in Runnymede

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Typical prices in Runnymede

Mid-range finish, South East prices, including VAT. The budget adds design and engineering fees, Runnymede's building control charge and a 15% contingency.
ProjectBuilding workBudget to plan for
Single-storey extension, 25 m²£72,500 to £89,500£89,500 to £115,000
Double-storey extension, 40 m²£105,000 to £132,000£129,000 to £167,000
Dormer loft conversion, 30 m²£65,000 to £80,000£80,500 to £102,000
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 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 Runnymede

Runnymede council charges including VAT (plan and inspection combined)
WorkCharge
Extension up to 10 m² (full plans)£828
Extension 10 to 40 m² (full plans)£1,182
Larger extension, 40-100 m² (full plans)£1,639
Extension 10 to 40 m² (building notice)£1,182
Loft conversion up to 40 m²£1,182
Garage conversion£708

Runnymede charges £1,182 for building control on a 10 to 40 m² extension (full plans, including VAT): the 6th dearest of the 91 councils we checked, 41% above the typical council (£840). Source: Runnymede's building control charges, 1 April 2026. Inc VAT ("inclusive of VAT at 20%").

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 Runnymede compares with every council we checked.

Notes on Runnymede's schedule

Own schedule. Single charge, same for full plans and building notice. Loft figure is with dormer (without 958).

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 East

Building control for a 10 to 40 m² extension:

Questions people ask

How much does an extension cost in Runnymede?

A mid-range 25 m² single-storey extension in Runnymede costs about £72,500 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 fees and a 15% contingency, budget £89,500 to £115,000.

How much is building control in Runnymede?

Runnymede charges £1,182 (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 Runnymede?

A mid-range 30 m² dormer loft conversion in Runnymede costs about £65,000 to £80,000 including VAT for the building work, and about £80,500 to £102,000 with fees and a 15% contingency.

Before you get quotes