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 Oxford?
In Oxford, a dormer loft conversion typically costs £54,000–£76,000 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Prices across the South East are typically 12% above the UK average for this kind of work, which is reflected in the range for Oxford. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear dormer with en-suite | £54,000–£76,000 |
| Higher specification | £76,000–£95,000 |
What moves the price most:
- Scaffolding and access
- En-suite or bathroom
- Staircase position
- Fire safety upgrades to the existing house
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a dormer loft conversion in Oxford?
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.
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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
On a typical dormer loft conversion we handle:
- New staircase and fire-safe escape route
- Steel beams and new floor joists
- Building control completion certificate
- Measured survey and head-height check
- Party wall notices for shared walls
- Insulation, plastering, electrics and plumbing
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 Oxford
Commuter towns across the South East have many 1930s and post-war semis that suit rear extensions and hip-to-gable loft conversions.
Oxford sits in Oxfordshire. We cover the whole of Oxford, including postcodes OX1.
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
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 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 Oxford
How much does a dormer loft conversion cost in Oxford?
In Oxford, a dormer loft conversion typically costs £54,000–£76,000 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
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 Oxford?
Typically 6 to 9 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
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 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.