What is a garage conversion?
A garage conversion turns an integral or attached garage into habitable space, such as a study, playroom, bedroom or utility. The garage door is replaced with a wall and window, the floor is raised and insulated, and the walls and roof are brought up to building regulations.
How much does a garage conversion cost in Lewisham?
In Lewisham, a garage conversion typically costs £23,500–£39,000 for a single integral garage, including VAT at 20% (standard rate). The guide for Lewisham reflects typical costs in London, roughly 30% above the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A single integral garage | £23,500–£39,000 |
| Higher specification | £39,000–£49,000 |
What moves the price most:
- Foundations under the old door opening
- Single or double garage
- Heating and flooring
- Whether planning permission is needed
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 garage conversion in Lewisham?
Approvals for a garage conversion in Lewisham follow the rules for England. In England converting an integral or attached garage usually does not need planning permission, unless a condition on the house removed permitted development rights (common on estates built in recent decades) or the house is listed. Building regulations approval is always needed.
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
Handled as part of most garage conversions:
- Floor raised with insulation and damp-proof membrane
- New wall and window to replace the garage door
- Drawings and building control application
- Foundation check under the garage door opening
- Building control completion
- Wall and ceiling insulation
How long does it take?
Expect 3 to 6 weeks on site. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Lewisham
Space is at a premium in London, so homeowners often build out into the side return or up into the roof rather than move.
Our Lewisham coverage includes postcode districts SE13 and SE22, and we also work in nearby places such as Forest Hill, Catford and Peckham.
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
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about garage conversions in Lewisham
How much does a garage conversion cost in Lewisham?
In Lewisham, a garage conversion typically costs £23,500–£39,000 for a single integral garage, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Who approves a garage conversion in Lewisham?
Planning matters in Lewisham go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Do I need building regulations approval?
Yes. Converting a garage to a habitable room needs building control approval for insulation, ventilation, fire safety and the new wall.
How long does it take?
Typically 3 to 6 weeks on site.
Can the floor be level with the house?
Yes. The garage floor is raised and insulated to match the house floor level.