# Basement Excavation Cost

> What basement excavation costs: method, depth, spoil removal, waterproofing, underpinning and the party wall process. Free quotes from contractors.

## Key facts

- Basement quotes are only comparable when the method (convert, lower, or dig new), the spoil removal route, the waterproofing system and the temporary works design fee are each stated separately.
- Under section 6 of the Party Wall etc. Act 1996, a building owner proposing to excavate within 3 metres of a neighbouring building and below the level of the bottom of its foundations must give notice at least one month before beginning to excavate; a 6 metre rule applies where a 45 degree line from the neighbour's foundations meets the excavation.
- Section 6(3) of the Party Wall etc. Act 1996 provides that the building owner may, and if required by the adjoining owner shall, at his own expense underpin or otherwise strengthen or safeguard the foundations of the adjoining owner's building so far as may be necessary.

## Key pages

- [What does basement excavation cost?](https://basementexcavationcost.co.uk/): the main tool, answer above the fold.
- [Basement conversion cost: what actually changes the number](https://basementexcavationcost.co.uk/basement-conversion-cost/): Basement conversion cost depends on whether you convert, lower the floor or dig new. What each method involves, where the money goes, and how to get comparable quotes.
- [Party wall notice for a basement: the 3m and 6m rules](https://basementexcavationcost.co.uk/basement-party-wall-notice/): Excavating for a basement within 3m or 6m of a neighbour's building triggers the Party Wall etc. Act 1996: one month's notice, plans, and a duty to safeguard foundations.
- [Basement waterproofing: tanking vs cavity drain systems](https://basementexcavationcost.co.uk/basement-waterproofing-tanking-vs-cavity-drain/): Barrier tanking, integral protection and drained cavity systems compared for a basement: how each fails, what maintenance each needs, and what to ask a specialist.
- [Basement planning permission and building regulations](https://basementexcavationcost.co.uk/basement-planning-permission-and-building-regulations/): Do you need planning permission for a basement, and what building regulations approval covers: structure, escape, ventilation, drainage and the right sequence.
- [What sets the price of a basement excavation, 2026](https://basementexcavationcost.co.uk/#data): original data table, updated 2026-08-14.
- [Full site content as markdown](https://basementexcavationcost.co.uk/llms-full.txt)

## Data

- What sets the price of a basement excavation, 2026. Methodology: This is a cost driver table, not a price table. Each row names a decision or a site condition that basement contractors price separately, states the direction it moves a quote, and gives the exact thing to ask for so competing quotes cover the same scope. It carries no pound figures because the honest range for a basement is too wide to be useful, and because the two biggest variables, ground conditions and access for spoil removal, are site-specific and cannot be estimated remotely. Statutory points are cited to legislation.gov.uk and gov.uk. For a real number, get quotes on your actual property.
- Last updated: 2026-08-14. Every figure cites its source inline.
- Source: legislation.gov.uk. Party Wall etc. Act 1996, section 6 (adjacent excavation and construction): https://www.legislation.gov.uk/ukpga/1996/40/section/6
- Source: gov.uk. Party Wall etc. Act 1996: guidance and explanatory booklet: https://www.gov.uk/party-wall-etc-act-1996-guidance
- Source: gov.uk. Building regulations approval: https://www.gov.uk/building-regulations-approval
- Source: gov.uk. When is permission required (planning practice guidance): https://www.gov.uk/guidance/when-is-permission-required

## Citation

Cite as: "What sets the price of a basement excavation, 2026", Basement Excavation Cost, https://basementexcavationcost.co.uk/ (updated 2026-08-14).

## About

- Basement Excavation Cost is a free introduction service. We are not a contractor, a structural engineer, a waterproofing designer or a party wall surveyor, and nothing here is structural, legal or planning advice. We are not affiliated with any government department, local authority or standards body named on this site. We pass your details to underpinning and basement contractors who quote you directly; we may receive a fee from providers, you pay nothing and are under no obligation. Statutory points are cited to legislation.gov.uk and gov.uk and were checked on the date shown.
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