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 Llanelli?
In Llanelli, a dormer loft conversion typically costs £44,000–£62,500 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Building costs in Wales run about 8% below the UK average, and the figures for Llanelli 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 | £44,000–£62,500 |
| Higher specification | £62,500–£78,000 |
The biggest cost drivers are:
- Dormer size and roof structure
- Built-in storage and finishes
- Fire safety upgrades to the existing house
- En-suite or bathroom
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 dormer loft conversion in Llanelli?
Approvals for a dormer loft conversion in Llanelli 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.
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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
What we take care of:
- New staircase and fire-safe escape route
- Building control completion certificate
- Measured survey and head-height check
- Party wall notices for shared walls
- Drawings and structural calculations
- Steel beams and new floor joists
How long does it take?
Allow 6 to 9 weeks on site. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Llanelli
Terraced houses in Welsh towns often have narrow plots, which suits rear and side return extensions and rear dormers.
Our Llanelli coverage includes postcode districts SA15, and we also work in nearby places such as Gorseinon, Swansea and Ammanford.
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
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about dormer loft conversions in Llanelli
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.
Do you build dormer loft conversions in Llanelli?
Yes. We build dormer loft conversions across Llanelli, including postcodes SA15. Every project starts with a free home visit.
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.
How much does a dormer loft conversion cost in Llanelli?
In Llanelli, 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.
Do I need planning permission for a dormer loft conversion in Llanelli?
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.