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 Market Harborough?
In Market Harborough, a dormer loft conversion typically costs £45,500–£64,500 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). That range is adjusted for the East Midlands, where domestic building work typically costs around 5% below the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear dormer with en-suite | £45,500–£64,500 |
| Higher specification | £64,500–£80,500 |
The biggest cost drivers are:
- Built-in storage and finishes
- Dormer size and roof structure
- Scaffolding and access
- Fire safety upgrades to the existing house
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 Market Harborough?
Approvals for a dormer loft conversion in Market Harborough follow the rules for 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
Handled as part of most dormer loft conversions:
- Dormer structure, roof covering and windows
- Building control completion certificate
- Insulation, plastering, electrics and plumbing
- New staircase and fire-safe escape route
- Steel beams and new floor joists
- Drawings and structural calculations
How long does it take?
Build time is typically 6 to 9 weeks on site. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Market Harborough
The East Midlands has a mix of red-brick terraces, inter-war semis and newer estates, so rear extensions and garage conversions are common projects.
Our Market Harborough coverage includes postcode districts LE16, and we also work in nearby places such as Corby, Kettering and Wigston Magna.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 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 Market Harborough
How long does it take?
Usually 6 to 9 weeks on site.
Who approves a dormer loft conversion in Market Harborough?
Planning matters in Market Harborough go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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.
How much does a dormer loft conversion cost in Market Harborough?
In Market Harborough, a dormer loft conversion typically costs £45,500–£64,500 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.
