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 Westminster?
In Westminster, a hip-to-gable loft conversion typically costs £71,500–£101,500 for a hip-to-gable with rear dormer, including VAT at 20% (standard rate). Prices across London are typically 30% above the UK average for this kind of work, which is reflected in the range for Westminster. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A hip-to-gable with rear dormer | £71,500–£101,500 |
| Higher specification | £101,500–£127,000 |
What moves the price most:
- Size of the rear dormer
- Gable wall construction and finish
- Roof tile matching
- 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 Westminster?
Whether you need planning permission depends on your house and its location 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
The work we manage on a hip-to-gable loft conversion:
- Roof extension and rear dormer
- Insulation, electrics, plumbing and plastering
- Survey and planning check
- Staircase and fire-safe escape route
- Building control sign-off
- Steel beams and floor joists
How long does it take?
The build itself usually takes 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 Westminster
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
If your home is in Westminster or close by in Bermondsey, Brixton and Battersea, a free home visit is the first step.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about hip-to-gable loft conversions in Westminster
Will I need building regulations approval?
Yes. All loft conversions to habitable rooms need building control approval for structure, fire safety, insulation and stairs.
How long does a hip-to-gable loft conversion take in Westminster?
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 Westminster?
In Westminster, a hip-to-gable loft conversion typically costs £71,500–£101,500 for a hip-to-gable with rear dormer, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Can the gable be brick?
Yes. We match the existing finish, whether brick, render or pebbledash.
Is a hip-to-gable conversion permitted development?
Often yes in England, within the 50 cubic metre roof volume limit for semi-detached and detached houses. It is not permitted development in conservation areas or where rights have been removed.