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 Caernarfon?
In Caernarfon, 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 Caernarfon. 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 |
What moves the price most:
- Bathroom and plumbing
- Scaffolding to three sides
- Roof tile matching
- Gable wall construction and finish
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a hip-to-gable loft conversion in Caernarfon?
Before anything is built in Caernarfon, we confirm which approvals apply in Wales. In Wales a hip-to-gable conversion may be permitted development within roof volume limits; corner plots and conservation areas usually need permission.
The Party Wall etc. Act 1996 applies in Wales, so notices must be served before work on a shared wall, on the boundary, or excavation close to a neighbour’s foundations.
We check this for your address before design work starts, so there are no surprises later.
What we handle
Handled as part of most hip-to-gable loft conversions:
- Roof extension and rear dormer
- Insulation, electrics, plumbing and plastering
- Survey and planning check
- Building control sign-off
- Drawings and structural calculations
- Staircase and fire-safe escape route
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 Caernarfon
Wales has many terraced valley streets, stone cottages and post-war estates, so extension designs are shaped by slopes, materials and local character.
From LL55 outwards, we take on projects throughout Caernarfon and the surrounding parts of Gwynedd.
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 pricing
Design options, then a fixed quote based on the chosen drawings and 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 Caernarfon
How much does a hip-to-gable loft conversion cost in Caernarfon?
In Caernarfon, 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.
Do I need planning permission for a hip-to-gable loft conversion in Caernarfon?
In Wales a hip-to-gable conversion may be permitted development within roof volume limits; corner plots and conservation areas usually need permission.
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.
Who approves a hip-to-gable loft conversion in Caernarfon?
Planning matters in Caernarfon go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How long does it take?
Typically 7 to 10 weeks on site.
Will I need building regulations approval?
Yes. All loft conversions to habitable rooms need building control approval for structure, fire safety, insulation and stairs.
