What is a dormer loft conversion?
A dormer loft conversion adds a box-shaped structure to the rear roof slope, creating vertical walls and full headroom across most of the new room. It is the most common loft conversion in the UK because it works on terraced, semi-detached and detached houses.
How much does a dormer loft conversion cost in Keighley?
In Keighley, a dormer loft conversion typically costs £44,500–£63,000 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Building costs in Yorkshire and the Humber run about 7% below the UK average, and the figures for Keighley are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear dormer with en-suite | £44,500–£63,000 |
| Higher specification | £63,000–£79,000 |
Your quote will depend mainly on:
- En-suite or bathroom
- Scaffolding and access
- Dormer size and roof structure
- Built-in storage and finishes
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a dormer loft conversion in Keighley?
Here is how the rules work for a dormer loft conversion in England. In England a rear dormer is often permitted development if the extra roof volume is no more than 40 cubic metres on a terraced house or 50 on other houses, it does not face the road, sits no higher than the ridge and is set back from the eaves, with matching materials and obscure-glazed side windows. Balconies, front dormers and work in conservation areas need planning permission.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
Handled as part of most dormer loft conversions:
- Building control completion certificate
- Dormer structure, roof covering and windows
- New staircase and fire-safe escape route
- Insulation, plastering, electrics and plumbing
- Drawings and structural calculations
- Measured survey and head-height check
How long does it take?
Allow 6 to 9 weeks on site. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Keighley
In Yorkshire, through-terraces and back-to-backs have particular constraints, while semis and detached houses suit larger extensions.
We work across Keighley and neighbouring areas such as Bingley, Shipley and Guiseley. Postcodes we cover in Keighley include BD21.
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 dormer loft conversions in Keighley
What fire safety is required?
Building regulations require a safe escape route. Converting a two-storey house to three storeys usually means a protected stairway with fire doors to habitable rooms and mains-wired smoke alarms.
How long does a dormer loft conversion take in Keighley?
Typically 6 to 9 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
How much does a dormer loft conversion cost in Keighley?
In Keighley, a dormer loft conversion typically costs £44,500–£63,000 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
How much head height do I need?
Ideally at least 2.2 metres from the top of the ceiling joists to the underside of the ridge. Less can still work with a dormer, but we check this at the survey.
Will I need to move out?
No. Most of the work is done from scaffolding and the roof. The new staircase is formed near the end, which causes a few days of disruption.