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 Lincolnshire?
In Lincolnshire, a dormer loft conversion typically costs £45,500–£64,500 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Building costs in the East Midlands run about 5% below the UK average, and the figures for Lincolnshire are adjusted to reflect that. 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 |
What moves the price most:
- En-suite or bathroom
- Dormer size and roof structure
- Scaffolding and access
- Staircase position
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 Lincolnshire?
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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
Handled as part of most dormer loft conversions:
- Party wall notices for shared walls
- Measured survey and head-height check
- Steel beams and new floor joists
- New staircase and fire-safe escape route
- Insulation, plastering, electrics and plumbing
- Drawings and structural calculations
How long does it take?
Expect 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 Lincolnshire
In the East Midlands, many estates built since the 1960s have integral garages that convert well into a study or bedroom.
Towns we cover in Lincolnshire include Lincoln, Grimsby, Scunthorpe, Boston, Grantham and Cleethorpes.
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 Lincolnshire
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.
How long does a dormer loft conversion take in Lincolnshire?
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 Lincolnshire?
In Lincolnshire, 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.
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.