Basement and cellar conversions · Bath

Basement and cellar conversions in Bath

Basement and cellar conversions for homes in Bath and the surrounding parts of Somerset, designed around your house and built by our teams under a single written contract.

Covering Bath

Our coverage around Bath (BA1) also includes Trowbridge (8 miles to the south-east) and Kingswood.

Homes in the South West

In the South West, matching local stone, render or slate is often the main design question, and conservation areas and listed buildings are common in historic towns.

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.

  • Damp and structural survey
  • Waterproofing design and installation
  • Lightwells and windows for daylight and escape

What will a basement conversion cost?

Guide prices for basement and cellar conversions, including VAT where it applies. Your fixed price is confirmed in writing after the survey.

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

How is a basement conversion approved in Bath?

English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.

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

What can affect a basement conversion?

  • New basements nearly always involve the Party Wall Act in England and Wales.
  • Headroom of about 2.1 m or more is needed, which may mean lowering the floor.

What happens after I enquire?

  1. Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
  2. Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
  3. Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
  4. We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.

Basement and cellar conversions: common questions

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.

How long does it take?

About 6 to 12 weeks for a cellar conversion and 16 to 30 weeks for a new basement.

How do I get a price for basement and cellar conversions in Bath?

Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.

Basement and cellar conversions near Bath

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

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