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 Blackwood?
In Blackwood, 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). That range is adjusted for Wales, where domestic building work typically costs around 8% below the national average. 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 biggest cost drivers are:
- Size of the rear dormer
- Bathroom and plumbing
- Roof tile matching
- Scaffolding to three sides
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 Blackwood?
The approval route for Blackwood is set by planning law 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.
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
On a typical hip-to-gable loft conversion we handle:
- Survey and planning check
- Building control sign-off
- Gable wall built in brick or block and finished to match
- Staircase and fire-safe escape route
- Drawings and structural calculations
- Insulation, electrics, plumbing and plastering
How long does it take?
Expect 7 to 10 weeks on site. Before that, surveys, drawings and approvals usually take 6 to 12 weeks, longer if the council asks for changes.
Building in Blackwood
Wales has many terraced valley streets, stone cottages and post-war estates, so extension designs are shaped by slopes, materials and local character.
Our Blackwood coverage includes postcode districts NP12, and we also work in nearby places such as Risca, Caerphilly and Pontypridd.
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
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 Blackwood
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.
Do I need planning permission for a hip-to-gable loft conversion in Blackwood?
In Wales a hip-to-gable conversion may be permitted development within roof volume limits; corner plots and conservation areas usually need permission.
Will I need building regulations approval?
Yes. All loft conversions to habitable rooms need building control approval for structure, fire safety, insulation and stairs.
Who approves a hip-to-gable loft conversion in Blackwood?
Planning matters in Blackwood go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How much does a hip-to-gable loft conversion cost in Blackwood?
In Blackwood, 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.
