Dormer loft conversions in Crawley

Covering Crawley

We work in Crawley (RH11, RH77) and the places around it, including Horley, Horsham and East Grinstead.

Homes in the South East

The South East has a lot of 1930s and post-war semi-detached housing, well suited to rear extensions and hip-to-gable loft conversions, alongside period properties in conservation areas that need a more careful design.

What goes into 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
Lawful development certificate or planning drawings
Staircase, insulation and plasterboard

How much should I budget for a dormer loft conversion?

Guide prices for dormer loft conversions, including VAT where it applies. Your fixed price is confirmed in writing after the survey.

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

What approvals does a dormer loft conversion need in England?

English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.

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. Houses in conservation areas, National Parks and National Landscapes cannot use these roof-extension rights, so dormers there need planning permission (a rooflight-only conversion can still be permitted development), and flats always need permission.

What should Crawley homeowners check first?

Dormer cheeks close to a shared wall can trigger the Party Wall Act.
L-shaped dormers are common on Victorian terraces with a rear outrigger.

How does the project run?

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
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.

Questions about a dormer loft conversion in Crawley

How long does a dormer conversion take?

Around 8 to 12 weeks on site.

Can a dormer include a bathroom?

Yes. The full head height in a dormer makes it the best place for a shower room or en-suite.

Do you work in Crawley?

Yes. Crawley is within our coverage for dormer loft conversions, along with nearby Horley and Horsham.

Also covering

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