Price guide

How much does a loft conversion cost in the Cotswolds?

Short answer

A Gloucester builder publishes £18,000 to £32,000 for a roof light conversion and £26,000 to £48,000 for a rear dormer. An Oxford firm says most cost £45,000 to £75,000. National figures are higher. In the Cotswolds, a dormer often needs planning permission first. Get three written quotes.

Updated 15 October 2026 · 2 min read · 8 sources

What local firms publish

Local published prices for a simple loft conversion start at about £18,000. The price rises with the size and the type of conversion. We found three firms that publish prices for this area.

Loft conversion prices published by firms near the Cotswolds
Firm (base)	Job	Published price
Gloucester Building (Gloucester)	Roof light (Velux) conversion	£18,000 to £32,000
Gloucester Building (Gloucester)	Rear dormer	£26,000 to £48,000
Gloucester Building (Gloucester)	Hip-to-gable	£28,000 to £46,000
Gloucester Building (Gloucester)	Hip-to-gable with full-width rear dormer	£36,000 to £55,000
Crawford Construction (Oxford)	Most loft conversions, 2026	£45,000 to £75,000
Crawford Construction (Oxford)	Extra cost of an en suite	£8,000 to £12,000
Moduloft (factory-built floors)	Completed jobs in Oxfordshire and the Cotswolds	£91,910 to £215,886

Prices that each firm publishes on its own website, checked on 15 October 2026. Gloucester Building's page is dated 16 March 2026. Moduloft builds a whole new floor in a factory, so its jobs are a different kind of conversion. Most pages do not say if VAT is included. Sources: Gloucester Building (Gloucester): loft conversion cost (16 March 2026), Crawford Construction (Oxford): loft conversion cost calculator, 2026, Moduloft (North Yorkshire): Oxfordshire and Cotswolds loft conversions.

National prices by type

A national guide gives higher figures. These are national, not Cotswold quotes.

National loft conversion prices by type
Type	National price	Price range chart
Roof light (Velux)	£30,000 to £45,000
Dormer	£45,000 to £75,000
Hip-to-gable	£55,000 to £85,000
Mansard	£70,000 to £120,000 or more

National figures from Homebuilding & Renovating (updated 29 July 2026), checked on 15 October 2026. The page does not say if these ranges include VAT. They are not local prices. Sources: Homebuilding & Renovating: loft conversion costs (national, updated 29 July 2026).

Fees to add

Fees for approvals and notices are often extra. Ask each firm what its price includes.

Fees for a loft conversion
Fee	Amount	Source
Building control, loft up to 100 m² (full plans)	£655 including VAT	Cotswold District Council, 2026/27
Building control, loft up to 100 m² (building notice)	£720 including VAT	Cotswold District Council, 2026/27
Householder planning application, England	£548	Planning Portal, from 1 April 2026
Party wall surveyor, per neighbour	£700 to £1,500	Gloucester Building

Official fees from the Cotswold District Council fee schedule (20 March 2026) and the Planning Portal fee schedule. The party wall figure is published by Gloucester Building. All checked on 15 October 2026. Sources: Cotswold District Council: Building control fees 2026/27 (PDF, 20 March 2026), Planning Portal: Application fees, England, from 1 April 2026 (PDF), Gloucester Building (Gloucester): loft conversion cost (16 March 2026).

What makes a loft conversion cost more in the Cotswolds

Planning permission. On designated land, roof enlargements are not permitted development. Much of the Cotswolds is designated land, so a dormer usually needs a planning application.

Old roofs. Old timbers may need strengthening, and a stone slate roof costs more to open up and make good.

Fire safety. A protected stairway with fire-resisting doors is usually needed, and linked smoke alarms.

Shared walls. In a terrace, new beams often go into the party wall, so you need party wall notices.

A listed house. A conversion that affects its character needs listed building consent.

How to get a fair price

Prices vary a lot. Get at least three written quotes for the same design.

Ask if the price includes the stairs, insulation, windows, electrics and plastering.
Ask if the structural engineer and building control fees are included.
Ask if VAT is included.
Ask how the roof will be kept dry during the work.
Agree payment stages linked to work done.

Questions

What is the cheapest type of loft conversion?

A roof light conversion, which keeps the roof shape. One Gloucester builder publishes £18,000 to £32,000 for this type.

Does a dormer in the Cotswolds need planning permission?

Usually, yes, if the house is in the National Landscape or a conservation area. Roof enlargements are not permitted development on that land.

Why do loft conversion prices vary so much?

The type, size and finish vary. A dormer or mansard needs more structure than roof lights. An en suite, a new staircase and a stone slate roof all add cost.