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 Sutton?
In Sutton, 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). That range is adjusted for London, where domestic building work typically costs around 30% above the national average. 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 |
Your quote will depend mainly on:
- Staircase design
- Gable wall construction and finish
- Roof tile matching
- 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 Sutton?
Approvals for a hip-to-gable loft conversion in Sutton 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.
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.
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:
- Building control sign-off
- Staircase and fire-safe escape route
- Gable wall built in brick or block and finished to match
- Roof extension and rear dormer
- Survey and planning check
- Drawings and structural calculations
How long does it take?
The build itself usually takes 7 to 10 weeks on site. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Sutton
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
We work across Sutton and neighbouring areas such as Carshalton, Wallington and Morden. Postcodes we cover in Sutton include CR44, SM1 and SM2.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 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 Sutton
How much does a hip-to-gable loft conversion cost in Sutton?
In Sutton, 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.
Who approves a hip-to-gable loft conversion in Sutton?
Planning matters in Sutton go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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.
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.
