Basement and cellar conversions · Bristol

Basement and cellar conversions in Bristol

We design and build basement and cellar conversions throughout Bristol, with a fixed price in writing for the agreed specification and one point of contact.

Covering Bristol

We cover homes across Bristol, planned from survey to sign-off.

Homes in the South West

The South West mixes stone and render cottages, Victorian terraces in the larger towns and modern estates, and many historic centres are conservation areas where materials and roof shapes are closely controlled.

What is included in a basement conversion in Bristol?

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.

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

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

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

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

What approvals does a basement conversion need in England?

Projects in England go through two separate checks. Planning (or confirmation that the work is permitted development) comes from the district, borough or unitary council, and building regulations approval comes from the council’s building control team or a registered building control approver. Where work touches a shared wall or digs near a neighbour’s foundations, the Party Wall etc. Act 1996 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.

What happens after I enquire?

  1. Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
  2. Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
  3. Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
  4. Construction and completion. One site lead co-ordinates every trade through to the building control certificate.

Basement and cellar conversions: common questions

Does a cellar conversion need planning permission?

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

Will my neighbours be affected?

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

Do you work in Bristol?

Yes. Bristol is within our coverage for basement and cellar conversions, along with nearby Bristol and Bristol.

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

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