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 Cardiff?
In Cardiff, a hip-to-gable loft conversion typically costs £50,500–£72,000 for a hip-to-gable with rear dormer, including VAT at 20% (standard rate). Prices across Wales are typically 8% below the UK average for this kind of work, which is reflected in the range for Cardiff. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A hip-to-gable with rear dormer | £50,500–£72,000 |
| Higher specification | £72,000–£90,000 |
The main things that change the cost:
- Gable wall construction and finish
- Size of the rear dormer
- Roof tile matching
- Bathroom and plumbing
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 Cardiff?
Approvals for a hip-to-gable loft conversion in Cardiff follow the rules for Wales. In Wales a hip-to-gable conversion may be permitted development within roof volume limits; corner plots and conservation areas usually need permission.
Building regulations in Wales are set by the Welsh Government. Approval comes from the council’s building control service or a registered building control approver, with inspections during the work and a completion certificate at the end.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
What we take care of:
- Insulation, electrics, plumbing and plastering
- Steel beams and floor joists
- Drawings and structural calculations
- Roof extension and rear dormer
- Survey and planning check
- Building control sign-off
How long does it take?
Allow 7 to 10 weeks on site. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Cardiff
Wales has many terraced valley streets, stone cottages and post-war estates, so extension designs are shaped by slopes, materials and local character.
From CF10 outwards, we take on projects throughout Cardiff and the surrounding parts of South Glamorgan.
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 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 Cardiff
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.
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 much does a hip-to-gable loft conversion cost in Cardiff?
In Cardiff, a hip-to-gable loft conversion typically costs £50,500–£72,000 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 Cardiff?
Planning matters in Cardiff go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Do I need planning permission for a hip-to-gable loft conversion in Cardiff?
In Wales a hip-to-gable conversion may be permitted development within roof volume limits; corner plots and conservation areas usually need permission.