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 West Sussex?
In West Sussex, 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). We start from a UK-wide guide and adjust it for the South East, where labour and materials are typically about 12% above 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:
- Staircase design
- Size of the rear dormer
- Scaffolding to three sides
- Bathroom and plumbing
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a hip-to-gable loft conversion in West Sussex?
Approvals for a hip-to-gable loft conversion in West Sussex follow the rules for 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.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
Handled as part of most hip-to-gable loft conversions:
- Survey and planning check
- Insulation, electrics, plumbing and plastering
- Steel beams and floor joists
- Building control sign-off
- Gable wall built in brick or block and finished to match
- Staircase and fire-safe escape route
How long does it take?
Build time is typically 7 to 10 weeks on site. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in West Sussex
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.
Towns we cover in West Sussex include Crawley, Worthing, Bognor Regis, Littlehampton, Horsham and Haywards Heath.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 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
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about hip-to-gable loft conversions in West Sussex
Can the gable be brick?
Yes. We match the existing finish, whether brick, render or pebbledash.
Will it look strange next to my neighbour?
On a pair of semis the roofs will no longer match unless your neighbour does the same. Many streets already have several converted roofs.
How long does a hip-to-gable loft conversion take in West Sussex?
Typically 7 to 10 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
How much does a hip-to-gable loft conversion cost in West Sussex?
In West Sussex, 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.
Will I need building regulations approval?
Yes. All loft conversions to habitable rooms need building control approval for structure, fire safety, insulation and stairs.