What is a basement conversion?
A basement conversion turns an existing cellar into living space, or excavates a new basement under the house or garden. Waterproofing, structural support and daylight are the main design challenges.
How much does a basement conversion cost in Strabane?
In Strabane, a basement conversion typically costs £1,650–£2,750 per m² for converting an existing cellar, including VAT at 20% (standard rate). For a typical 30 m² project that is roughly £49,500–£82,500. Prices across Northern Ireland are typically 14% below the UK average for this kind of work, which is reflected in the range for Strabane. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (21 m²) | £34,500–£58,000 |
| Typical project (30 m²) | £49,500–£82,500 |
| Larger project (42 m²) | £69,500–£115,500 |
| Rate per m² | £1,650–£2,750 |
What moves the price most:
- Floor lowering and underpinning
- Ground water and access
- Agreements with neighbours on shared walls
- Waterproofing system
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a basement conversion in Strabane?
The approval route for Strabane is set by planning law in Northern Ireland. In Northern Ireland converting an existing cellar usually does not need planning permission; new excavation and external changes may.
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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
The work we manage on a basement conversion:
- Insulation, ventilation and drainage pumps
- Structural and ground survey
- Building control sign-off
- Written agreement with neighbours on shared walls
- Underpinning or new structure where needed
- Waterproofing design (tanking or cavity drain membrane)
How long does it take?
Allow 8 to 16 weeks for a cellar conversion; longer for new excavation. Allow time beforehand for drawings and approvals, usually 3 to 5 months.
Building in Strabane
Across Northern Ireland, bungalows and chalet bungalows are common, so loft conversions and rear extensions are popular projects.
We work across Strabane and neighbouring areas such as Derry, Omagh and Limavady. Postcodes we cover in Strabane include BT82.
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 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 basement conversions in Strabane
How do you keep a basement dry?
With a waterproofing system designed to BS 8102, typically a cavity drain membrane with a sump pump, or a tanking system.
How much does a basement conversion cost in Strabane?
In Strabane, a basement conversion typically costs £1,650–£2,750 per m² for converting an existing cellar, including VAT at 20% (standard rate). A typical 30 m² project comes to roughly £49,500–£82,500. Your fixed price depends on the survey and drawings.
Do I need planning permission for a basement conversion in Strabane?
In Northern Ireland converting an existing cellar usually does not need planning permission; new excavation and external changes may.
Do you build basement conversions in Strabane?
Yes. We build basement conversions across Strabane, including postcodes BT82. Every project starts with a free home visit.
Can a basement be a bedroom?
Yes, with a suitable escape route such as a lightwell window or protected stair.
Is new excavation worth it?
It can be in high-value areas, but costs are high. We give a feasibility view before design starts.