Basement and cellar conversions in Farnham

Covering Farnham

Farnham is about 10 miles west of Guildford. We also cover Aldershot (3 miles to the north-east), Fleet and Farnborough.

Homes in the South East

The South East has a lot of 1930s and post-war semi-detached housing, well suited to rear extensions and hip-to-gable loft conversions, alongside period properties in conservation areas that need a more careful design.

What does a basement conversion involve?

Everything below ground depends on keeping water out. We design the waterproofing system (usually a cavity drain membrane with a pump, or tanking) to the relevant British Standard guidance, then add insulation, ventilation, light and an escape route. New basements involve underpinning and a party wall process and are designed with a structural engineer.

Underpinning or lowering the floor where needed
Ventilation, heating and electrics
Finished floors, walls and ceilings

What is the guide price for a basement conversion in Farnham?

Typical ranges for basement and cellar conversions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.

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

Planning and building rules in Farnham

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. Digging a new basement or adding a lightwell often does, and many councils have basement policies.

What can change the price or programme?

A pump for the drainage system needs a battery back-up.
Headroom of about 2.1 m or more is needed, which may mean lowering the floor.

From first call to completion

Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
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.
We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.

What people ask before starting

How much does a basement conversion cost?

Converting an existing cellar costs about £1,900 to £3,000 per square metre including VAT. A new excavated basement is around £4,200 to £6,600 per square metre.

Will my neighbours be affected?

New basements usually need party wall agreements. We handle the notices and surveyors.

Do you work in Farnham?

Yes. Farnham is within our coverage for basement and cellar conversions, along with nearby Aldershot and Fleet.

Basement and cellar conversions in nearby towns

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