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 Peacehaven?
In Peacehaven, 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 Peacehaven. 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 |
The biggest cost drivers are:
- Fire safety upgrades to the existing house
- Built-in storage and finishes
- Dormer size and roof structure
- Staircase position
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a dormer loft conversion in Peacehaven?
The approval route for Peacehaven is set by planning law 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
From survey to sign-off, the job normally involves:
- Drawings and structural calculations
- Insulation, plastering, electrics and plumbing
- Party wall notices for shared walls
- New staircase and fire-safe escape route
- 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. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Peacehaven
Commuter towns across the South East have many 1930s and post-war semis that suit rear extensions and hip-to-gable loft conversions.
If your home is in Peacehaven or close by in Rottingdean, Seaford and Brighton, a free home visit is the first step.
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
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about dormer loft conversions in Peacehaven
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 much does a dormer loft conversion cost in Peacehaven?
In Peacehaven, 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.
How long does it take?
Usually 6 to 9 weeks on site.
Who approves a dormer loft conversion in Peacehaven?
Planning matters in Peacehaven 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.
