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 Swansea?
In Swansea, a dormer loft conversion typically costs £44,000–£62,500 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). We start from a UK-wide guide and adjust it for Wales, where labour and materials are typically about 8% below average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear dormer with en-suite | £44,000–£62,500 |
| Higher specification | £62,500–£78,000 |
The biggest cost drivers are:
- Built-in storage and finishes
- Staircase position
- Scaffolding and access
- Fire safety upgrades to the existing house
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 Swansea?
Approvals for a dormer loft conversion in Swansea follow the rules for Wales. In Wales roof enlargements such as rear dormers can be permitted development within volume limits and design conditions. Dormers facing a road, balconies and conservation-area work 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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
Handled as part of most dormer loft conversions:
- Measured survey and head-height check
- Party wall notices for shared walls
- Dormer structure, roof covering and windows
- Steel beams and new floor joists
- Insulation, plastering, electrics and plumbing
- Drawings and structural calculations
How long does it take?
Expect 6 to 9 weeks on site. Before that, surveys, drawings and approvals usually take 6 to 12 weeks, longer if the council asks for changes.
Building in Swansea
Wales has many terraced valley streets, stone cottages and post-war estates, so extension designs are shaped by slopes, materials and local character.
If your home is in Swansea or close by in Clydach, Gorseinon and Neath, a free home visit is the first step.
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 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 dormer loft conversions in Swansea
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.
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.
Do I need planning permission for a dormer loft conversion in Swansea?
In Wales roof enlargements such as rear dormers can be permitted development within volume limits and design conditions. Dormers facing a road, balconies and conservation-area work need permission.
How long does it take?
Usually 6 to 9 weeks on site.
Do you build dormer loft conversions in Swansea?
Yes. We build dormer loft conversions across Swansea, including postcodes SA1. Every project starts with a free home visit.
How much does a dormer loft conversion cost in Swansea?
In Swansea, a dormer loft conversion typically costs £44,000–£62,500 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.