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 Heywood?
In Heywood, a basement conversion typically costs £1,800–£3,000 per m² for converting an existing cellar, including VAT at 20% (standard rate). For a typical 30 m² project that is roughly £54,000–£90,000. The guide for Heywood reflects typical costs in the North West, roughly 6% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (21 m²) | £38,000–£63,000 |
| Typical project (30 m²) | £54,000–£90,000 |
| Larger project (42 m²) | £75,500–£126,000 |
| Rate per m² | £1,800–£3,000 |
What moves the price most:
- Floor lowering and underpinning
- Lightwells
- Existing cellar or new excavation
- Waterproofing system
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 basement conversion in Heywood?
The approval route for Heywood is set by planning law in England. In England converting an existing cellar with no external change usually does not need planning permission. New excavation, lightwells and changes to the front often do, and some councils, particularly in London, have specific basement policies.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
What we take care of:
- Party wall notices
- Lightwells and windows
- Underpinning or new structure where needed
- Structural and ground survey
- Building control sign-off
- Waterproofing design (tanking or cavity drain membrane)
How long does it take?
The build itself usually takes 8 to 16 weeks for a cellar conversion; longer for new excavation. Design and approvals come first and typically take 3 to 5 months, depending on the approval route.
Building in Heywood
Terraced streets across the North West often suit rear dormers and single-storey kitchen extensions.
Our Heywood coverage includes postcode districts OL10, and we also work in nearby places such as Middleton, Rochdale and Bury.
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
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 Heywood
Is new excavation worth it?
It can be in high-value areas, but costs are high. We give a feasibility view before design starts.
How much does a basement conversion cost in Heywood?
In Heywood, a basement conversion typically costs £1,800–£3,000 per m² for converting an existing cellar, including VAT at 20% (standard rate). A typical 30 m² project comes to roughly £54,000–£90,000. Your fixed price depends on the survey and drawings.
Do you build basement conversions in Heywood?
Yes. We build basement conversions across Heywood, including postcodes OL10. Every project starts with a free home visit.
Does a basement conversion need planning permission?
Converting an existing cellar without changing the outside usually does not. New excavation, lightwells and changes visible from outside usually do.
Can a basement be a bedroom?
Yes, with a suitable escape route such as a lightwell window or protected stair.