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 Armagh?
In Armagh, a dormer loft conversion typically costs £41,500–£58,500 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Building costs in Northern Ireland run about 14% below the UK average, and the figures for Armagh 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 | £41,500–£58,500 |
| Higher specification | £58,500–£73,000 |
What moves the price most:
- Scaffolding and access
- Built-in storage and finishes
- En-suite or bathroom
- Dormer size and roof structure
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 Armagh?
Approvals for a dormer loft conversion in Armagh follow the rules for Northern Ireland. In Northern Ireland a rear dormer can be permitted development if it does not face a road, sits no higher than the ridge and is set back at least 0.5 metres from the ridge, eaves, party wall and verges. Roof enlargements are not permitted development in conservation areas.
Northern Ireland has no Party Wall Act. Work on shared walls relies on agreement with the neighbour and common law, so we agree the arrangements 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
Handled as part of most dormer loft conversions:
- Building control completion certificate
- Measured survey and head-height check
- Written agreement with neighbours on shared walls
- New staircase and fire-safe escape route
- Steel beams and new floor joists
- Dormer structure, roof covering and windows
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 Armagh
Across Northern Ireland, bungalows and chalet bungalows are common, so loft conversions and rear extensions are popular projects.
Armagh sits in County Armagh. We cover the whole of Armagh, including postcodes BT60 and BT61.
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 pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 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 Armagh
How long does a dormer loft conversion take in Armagh?
Typically 6 to 9 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
Do I need planning permission for a dormer loft conversion in Armagh?
In Northern Ireland a rear dormer can be permitted development if it does not face a road, sits no higher than the ridge and is set back at least 0.5 metres from the ridge, eaves, party wall and verges. Roof enlargements are not permitted development in conservation areas.
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.
How much does a dormer loft conversion cost in Armagh?
In Armagh, a dormer loft conversion typically costs £41,500–£58,500 for a typical rear dormer with en-suite, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
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.
