Dormer loft conversions in Corsham

Covering Corsham

Our coverage around Corsham (SN13) also includes Chippenham, Calne and Trowbridge.

Homes in the South West

The South West mixes stone and render cottages, Victorian terraces in the larger towns and modern estates, and many historic centres are conservation areas where materials and roof shapes are closely controlled.

What is a dormer loft conversion?

A dormer loft conversion builds a box-shaped extension out from the rear slope of the roof, creating vertical walls and full head height across most of the new floor. It is the most popular type of loft conversion because it gives the most usable space for the cost.

Volume calculation and permitted development check
Dormer frame, roof covering and cladding
Staircase, insulation and plasterboard

How much should I budget for a dormer loft conversion?

Use these ranges to budget for dormer loft conversions; the survey turns them into a fixed price for the agreed specification.

Dormer loft conversions	Guide price incl. VAT
Rear dormer, bedroom only	£50,000 to £65,000
Full-width dormer with en-suite	£60,000 to £80,000
L-shaped dormer (over rear outrigger)	£65,000 to £90,000

Do you need permission for a dormer loft conversion in Corsham?

In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it applies.

In England many loft conversions are permitted development: the extra roof volume must stay within 40 m³ on a terraced house or 50 m³ on a semi or detached house, nothing can sit higher than the existing ridge, no dormer can face a road on the main elevation, and side windows must be obscure-glazed and non-opening below 1.7 m.

What can change the price or programme?

Dormers on the front of the house facing a road are not permitted development in England.
A flat dormer roof needs proper falls and a quality membrane.

What are the steps?

Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.

Dormer loft conversions: common questions

How much does a dormer loft conversion cost?

Typically £50,000 to £80,000 including VAT, and up to around £90,000 for an L-shaped dormer.

Is a dormer permitted development?

Rear dormers in England often are, within the 40 m³ (terrace) or 50 m³ (semi or detached) volume allowance. Front dormers facing a road are not.

Who deals with the council for a project in Corsham?

We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.

Also covering

Learn more about dormer loft conversions, or see every project we cover in Corsham.