What is a hip-to-gable loft conversion?

A hip-to-gable loft conversion replaces the sloping side (the hip) of a semi-detached or detached roof with a vertical gable wall. This extends the ridge and creates enough space for a staircase and a full-size room, usually combined with a rear dormer.
How much does a hip-to-gable loft conversion cost in Crawley?
In Crawley, a hip-to-gable loft conversion typically costs £61,500–£87,500 for a hip-to-gable with rear dormer, including VAT at 20% (standard rate). That range is adjusted for the South East, where domestic building work typically costs around 12% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A hip-to-gable with rear dormer | £61,500–£87,500 |
| Higher specification | £87,500–£109,500 |
What moves the price most:
- Scaffolding to three sides
- Bathroom and plumbing
- Gable wall construction and finish
- Staircase design
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a hip-to-gable loft conversion in Crawley?
Before anything is built in Crawley, we confirm which approvals apply in England. In England a hip-to-gable conversion is often permitted development within the 50 cubic metre roof volume limit for semi-detached and detached houses, provided the gable does not face a road and the house is not in a conservation area.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
We check this for your address before design work starts, so there are no surprises later.
What we handle
From survey to sign-off, the job normally involves:
- Roof extension and rear dormer
- Steel beams and floor joists
- Staircase and fire-safe escape route
- Gable wall built in brick or block and finished to match
- Drawings and structural calculations
- Survey and planning check
How long does it take?
Allow 7 to 10 weeks on site. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Crawley
The South East has a broad mix of housing, from Victorian terraces in the towns to post-war semis and newer estates, so extension types vary street by street.
Our Crawley coverage includes postcode districts RH11 and RH77, and we also work in nearby places such as Horley, Horsham and East Grinstead.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about hip-to-gable loft conversions in Crawley
Do you build hip-to-gable loft conversions in Crawley?
Yes. We build hip-to-gable loft conversions across Crawley, including postcodes RH11 and RH77. Every project starts with a free home visit.
How much does a hip-to-gable loft conversion cost in Crawley?
In Crawley, a hip-to-gable loft conversion typically costs £61,500–£87,500 for a hip-to-gable with rear dormer, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Is a hip-to-gable better than a dormer?
On a hipped roof, a dormer alone often leaves too little space for stairs. Combining hip-to-gable with a rear dormer gives the most room.
Will I need building regulations approval?
Yes. All loft conversions to habitable rooms need building control approval for structure, fire safety, insulation and stairs.
Can the gable be brick?
Yes. We match the existing finish, whether brick, render or pebbledash.
