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 Letchworth Garden City?
In Letchworth Garden City, a hip-to-gable loft conversion typically costs £58,500–£82,500 for a hip-to-gable with rear dormer, including VAT at 20% (standard rate). Building costs in the East of England run about 6% above the UK average, and the figures for Letchworth Garden City are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A hip-to-gable with rear dormer | £58,500–£82,500 |
| Higher specification | £82,500–£103,000 |
The biggest cost drivers are:
- Size of the rear dormer
- Gable wall construction and finish
- Staircase design
- Roof tile matching
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a hip-to-gable loft conversion in Letchworth Garden City?
Here is how the rules work for a hip-to-gable loft conversion 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
What we take care of:
- Roof extension and rear dormer
- Staircase and fire-safe escape route
- Insulation, electrics, plumbing and plastering
- Steel beams and floor joists
- Drawings and structural calculations
- Building control sign-off
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 Letchworth Garden City
Many towns in the East of England have estates built since the 1970s, where garage conversions and rear extensions are popular.
Projects in Letchworth Garden City (SG6 and SG7) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 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 Letchworth Garden City
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 it take?
Typically 7 to 10 weeks on site.
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.
Do you build hip-to-gable loft conversions in Letchworth Garden City?
Yes. We build hip-to-gable loft conversions across Letchworth Garden City, including postcodes SG6 and SG7. Every project starts with a free home visit.
How much does a hip-to-gable loft conversion cost in Letchworth Garden City?
In Letchworth Garden City, a hip-to-gable loft conversion typically costs £58,500–£82,500 for a hip-to-gable with rear dormer, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
