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 Hornchurch?
In Hornchurch, a dormer loft conversion typically costs £62,500–£88,500 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). The guide for Hornchurch reflects typical costs in London, roughly 30% above the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear dormer with en-suite | £62,500–£88,500 |
| Higher specification | £88,500–£110,500 |
The main things that change the cost:
- Scaffolding and access
- Fire safety upgrades to the existing house
- En-suite or bathroom
- Staircase position
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 Hornchurch?
Before anything is built in Hornchurch, we confirm which approvals apply 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.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
What we take care of:
- Party wall notices for shared walls
- Measured survey and head-height check
- Drawings and structural calculations
- New staircase and fire-safe escape route
- Steel beams and new floor joists
- Building control completion certificate
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 Hornchurch
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
Hornchurch sits in Greater London, about 15 miles east of central London. We cover the whole of Hornchurch, including postcodes RM11 and RM12.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 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 Hornchurch
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 long does a dormer loft conversion take in Hornchurch?
Typically 6 to 9 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
How much does a dormer loft conversion cost in Hornchurch?
In Hornchurch, a dormer loft conversion typically costs £62,500–£88,500 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Does a dormer loft conversion need planning permission?
A rear dormer is often permitted development in England, provided the extra roof volume is within 40 cubic metres on a terraced house or 50 on a semi-detached or detached house, and it does not face the road. Front dormers and houses in conservation areas usually need an application.
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.