Basement and cellar conversions in Eltham

Covering Eltham

Eltham is about 9 miles south-east of London. We also cover Blackheath (2 miles to the north-west), Welling and Catford.

Homes in London

London projects often mean working on period terraces with neighbours on both sides, tight access through the house and conservation area controls, so careful planning and party wall work matter as much as the build.

What goes into a basement conversion?

A basement conversion turns an existing cellar into dry, usable rooms, or excavates a new basement under a house. Converting an existing cellar is far simpler and cheaper than digging a new one, and often does not need planning permission.

Waterproofing design and installation
Lightwells and windows for daylight and escape
Ventilation, heating and electrics

How much should I budget for a basement conversion?

What basement and cellar conversions typically cost. These are guide ranges; the written quote for your house replaces them.

Basement and cellar conversions	Guide price incl. VAT
Existing cellar conversion	£1,900 to £3,000 per m²
New basement excavation	£4,200 to £6,600 per m²

What approvals does a basement conversion need in England?

In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it applies.

Converting an existing cellar with no external changes usually does not need planning permission in England.

What can change the price or programme?

New basements nearly always involve the Party Wall Act in England and Wales.
A pump for the drainage system needs a battery back-up.

From first call to completion

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
Construction and completion. One site lead co-ordinates every trade through to the building control certificate.

Your questions answered

Does a cellar conversion need planning permission?

Usually not if nothing changes outside. New basements and lightwells often do.

How do you keep a basement dry?

With a designed waterproofing system, usually a cavity drain membrane draining to a pump, sometimes combined with tanking.

Can you visit a house in Eltham to quote?

Yes. After a short call we arrange a site visit to measure up and agree what the design needs to do, then send a written price.

Basement and cellar conversions near Eltham

Learn more about basement and cellar conversions, or see every project we cover in Eltham.