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 Kilwinning?
In Kilwinning, a dormer loft conversion typically costs £46,500–£66,000 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Building costs in Scotland are close to the UK average, so the figures for Kilwinning are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear dormer with en-suite | £46,500–£66,000 |
| Higher specification | £66,000–£82,500 |
What moves the price most:
- Fire safety upgrades to the existing house
- En-suite or bathroom
- Staircase position
- Scaffolding and access
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 Kilwinning?
The approval route for Kilwinning is set by planning law in Scotland. In Scotland a dormer is permitted development (Class 1D) only on a roof slope that does not face a road, at least 10 metres from the boundary it faces, no wider than half the roof at the eaves, set at least 0.3 metres from the roof edges and with no increase in ridge height. It is not permitted development in a conservation area, and a building warrant is needed for a loft conversion.
Scotland has no Party Wall Act. Work on shared walls is governed by your title deeds, the Tenements (Scotland) Act 2004 for flats, and common law, so we agree arrangements with neighbours in writing before work starts.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
The work we manage on a dormer loft conversion:
- Building control completion certificate
- Steel beams and new floor joists
- Written agreement with neighbours on shared walls
- Drawings and structural calculations
- Insulation, plastering, electrics and plumbing
- Dormer structure, roof covering and windows
How long does it take?
The build itself usually takes 6 to 9 weeks on site. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Kilwinning
Scotland’s housing ranges from sandstone tenements and villas to post-war and modern estates, and the building warrant system shapes how projects are planned.
From KA13 outwards, we take on projects throughout Kilwinning and the surrounding parts of Ayrshire.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 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 handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about dormer loft conversions in Kilwinning
Do I need planning permission for a dormer loft conversion in Kilwinning?
In Scotland a dormer is permitted development (Class 1D) only on a roof slope that does not face a road, at least 10 metres from the boundary it faces, no wider than half the roof at the eaves, set at least 0.3 metres from the roof edges and with no increase in ridge height. It is not permitted development in a conservation area, and a building warrant is needed for a loft conversion.
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.
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.
Do you build dormer loft conversions in Kilwinning?
Yes. We build dormer loft conversions across Kilwinning, including postcodes KA13. Every project starts with a free home visit.
How much does a dormer loft conversion cost in Kilwinning?
In Kilwinning, a dormer loft conversion typically costs £46,500–£66,000 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.
