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 Blantyre?
In Blantyre, a basement conversion typically costs £1,850–£3,100 per m² for converting an existing cellar, including VAT at 20% (standard rate). For a typical 30 m² project that is roughly £55,500–£93,000. Prices in Scotland sit near the national average for this kind of work, and the range for Blantyre reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (21 m²) | £39,000–£65,000 |
| Typical project (30 m²) | £55,500–£93,000 |
| Larger project (42 m²) | £77,500–£130,000 |
| Rate per m² | £1,850–£3,100 |
What moves the price most:
- Existing cellar or new excavation
- Agreements with neighbours on shared walls
- Ground water and access
- Lightwells
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 basement conversion in Blantyre?
Before anything is built in Blantyre, we confirm which approvals apply in Scotland. In Scotland converting an existing cellar may not need planning permission, but a building warrant is needed, and new excavation usually needs planning permission.
In Scotland a building warrant is needed before work starts on most extensions, loft conversions and conversions. It is issued by the council’s building standards service. When the work is finished, a completion certificate is submitted and accepted by the council after inspection.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
The work we manage on a basement conversion:
- Building control sign-off
- Written agreement with neighbours on shared walls
- Lightwells and windows
- Electrics, heating and plastering
- Insulation, ventilation and drainage pumps
- Structural and ground survey
How long does it take?
Allow 8 to 16 weeks for a cellar conversion; longer for new excavation. Before that, surveys, drawings and approvals usually take 3 to 5 months, longer if the council asks for changes.
Building in Blantyre
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.
Projects in Blantyre (G71 and G72) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 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 Blantyre
How much does a basement conversion cost in Blantyre?
In Blantyre, a basement conversion typically costs £1,850–£3,100 per m² for converting an existing cellar, including VAT at 20% (standard rate). A typical 30 m² project comes to roughly £55,500–£93,000. Your fixed price depends on the survey and drawings.
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.
Do I need planning permission for a basement conversion in Blantyre?
In Scotland converting an existing cellar may not need planning permission, but a building warrant is needed, and new excavation usually needs planning permission.
Is new excavation worth it?
It can be in high-value areas, but costs are high. We give a feasibility view before design starts.
Who approves a basement conversion in Blantyre?
Planning matters in Blantyre go to the council covering your address, and the work needs a building warrant. We prepare and submit the applications for you.
Can a basement be a bedroom?
Yes, with a suitable escape route such as a lightwell window or protected stair.
