Estiquote

Local costs · South West · September 2026

How much does an extension cost in West Devon?

A mid-range 25 m² single-storey extension in West Devon costs about £65,500 to £81,000 including VAT, or £2,600 to £3,200 per m² at South West prices. West Devon charges £1,095 for building control on a 10 to 40 m² extension (full plans, including VAT): the 11th dearest of the 91 councils we checked, 30% above the typical council (£840), though its published schedule is older or undated. With design, a structural engineer, building control and a 15% contingency, budget £81,500 to £105,000.

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

Work out your project in West Devon

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Typical prices in West Devon

Mid-range finish, South West prices, including VAT. The budget adds design and engineering fees, West Devon's building control charge and a 15% contingency.
ProjectBuilding workBudget to plan for
Single-storey extension, 25 m²£65,500 to £81,000£81,500 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 West Devon

West Devon council charges including VAT (plan and inspection combined)
WorkCharge
Extension up to 10 m² (full plans)£695
Extension 10 to 40 m² (full plans)£1,095
Larger extension, up to 50 m² (medium band) (full plans)£1,095
Extension 10 to 40 m² (building notice)Not published
Loft conversion up to 40 m²£795
Garage conversion£695

West Devon charges £1,095 for building control on a 10 to 40 m² extension (full plans, including VAT): the 11th dearest of the 91 councils we checked, 30% above the typical council (£840), though its published schedule is older or undated. Source: West Devon's building control charges, April 2024 ("Fees from April 2024"). Inc 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 West Devon compares with every council we checked.

Notes on West Devon's schedule

Shared schedule: Devon Building Control Partnership (South Hams, Teignbridge, West Devon). Combined charge; bands <=10 / <=50 m2; larger = quote. Loft figure is up to 30 m2 (up to 100 m2 995).

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:

Questions people ask

How much does an extension cost in West Devon?

A mid-range 25 m² single-storey extension in West Devon 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 £81,500 to £105,000.

How much is building control in West Devon?

West Devon charges £1,095 (including VAT) for a 10 to 40 m² extension (full plans), according to its published schedule (April 2024 ("Fees from April 2024")).

How much does a loft conversion cost in West Devon?

A mid-range 30 m² dormer loft conversion in West Devon 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