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 Wiltshire?
In Wiltshire, a hip-to-gable loft conversion typically costs £56,000–£79,500 for a hip-to-gable with rear dormer, including VAT at 20% (standard rate). Prices in the South West sit near the national average for this kind of work, and the range for Wiltshire reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A hip-to-gable with rear dormer | £56,000–£79,500 |
| Higher specification | £79,500–£99,500 |
The main things that change the cost:
- Roof tile matching
- Size of the rear dormer
- Gable wall construction and finish
- Scaffolding to three sides
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 Wiltshire?
The approval route for Wiltshire is set by planning law 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.
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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
Handled as part of most hip-to-gable loft conversions:
- Insulation, electrics, plumbing and plastering
- Roof extension and rear dormer
- Steel beams and floor joists
- Survey and planning check
- Gable wall built in brick or block and finished to match
- Building control sign-off
How long does it take?
Build time is typically 7 to 10 weeks on site. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Wiltshire
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
Towns we cover in Wiltshire include Swindon, Salisbury, Trowbridge, Chippenham and Melksham.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 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 Wiltshire
Will I need building regulations approval?
Yes. All loft conversions to habitable rooms need building control approval for structure, fire safety, insulation and stairs.
Do you build hip-to-gable loft conversions in Wiltshire?
Yes. We build hip-to-gable loft conversions across Wiltshire, including postcodes BA12, BA13, BA14, BA15 and RG17. Every project starts with a free home visit.
Can the gable be brick?
Yes. We match the existing finish, whether brick, render or pebbledash.
How long does it take?
Typically 7 to 10 weeks on site.
How much does a hip-to-gable loft conversion cost in Wiltshire?
In Wiltshire, a hip-to-gable loft conversion typically costs £56,000–£79,500 for a hip-to-gable with rear dormer, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
