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 Birmingham?
In Birmingham, a dormer loft conversion typically costs £46,500–£66,000 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Building costs in the West Midlands are close to the UK average, so the figures for Birmingham are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear dormer with en-suite | £46,500–£66,000 |
| Higher specification | £66,000–£82,500 |
The biggest cost drivers are:
- Staircase position
- Built-in storage and finishes
- Dormer size and roof structure
- En-suite or bathroom
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 Birmingham?
Whether you need planning permission depends on your house and its location 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.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
The work we manage on a dormer loft conversion:
- Drawings and structural calculations
- Insulation, plastering, electrics and plumbing
- Dormer structure, roof covering and windows
- Party wall notices for shared walls
- Steel beams and new floor joists
- Building control completion certificate
How long does it take?
The build itself usually takes 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 Birmingham
Across the West Midlands, inter-war and post-war semis make up much of the housing, giving good scope for two-storey side extensions and hip-to-gable lofts.
Projects in Birmingham (B1, B2, B3 and B4) are surveyed in person before we quote, so the price reflects your actual property.
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 dormer loft conversions in Birmingham
How much does a dormer loft conversion cost in Birmingham?
In Birmingham, a dormer loft conversion typically costs £46,500–£66,000 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 a party wall agreement?
In England and Wales, if the conversion cuts into or builds on a shared wall, notices must be served under the Party Wall etc. Act 1996.
Do you build dormer loft conversions in Birmingham?
Yes. We build dormer loft conversions across Birmingham, including postcodes B1, B2, B3 and B4. 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.
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.