Party Wall Surveyors South West London

This guide uses one disclosed working definition. The current NHS South West London administrative area contains Croydon, Kingston upon Thames, Merton, Richmond upon Thames, Sutton and Wandsworth. That health-governance footprint is useful for organising six boroughs, but it is not a Party Wall Act, planning, postcode or general London boundary.

Start with the complete property address. The address identifies the local planning authority and the policy documents to check; a south-west London label or an SW postcode does not.

FindTheSurveyor does not carry out surveying work and this page does not claim that a surveyor covers any address. A complete verified request may be reviewed by the administrator, but submission and review do not guarantee a surveyor invitation, quote or introduction.

Why this guide uses six boroughs

The Integrated Care Boards (Establishment and Abolition) Order 2026 continued NHS South West London Integrated Care Board from 1 April 2026. Its Schedule specifies six local-authority areas: Croydon, Kingston upon Thames, Merton, Richmond upon Thames, Sutton and Wandsworth. The ICB’s current place list shows the same six.

That is a statutory NHS geography. It does not create one planning authority, alter a title boundary or decide whether the Party Wall etc. Act 1996 applies. This page adopts the six only as a transparent editorial scope.

One Act, six planning evidence packs

For ordinary property work, the statutory tests do not change between these six boroughs. Planning evidence does, and the current adopted position is materially different across the six authorities.

Croydon: the Croydon Local Plan 2018 remains adopted while its replacement is under examination. Paragraph 8.34 in the DM25 section requests a Basement Impact Assessment as part of the Flood Risk Assessment where the site is at groundwater risk; that is not a blanket BIA rule for every basement. Table 8.1 does not permit basement dwellings in Flood Zones 3a or 3b. The Party Wall surveyors for Croydon properties guide explains those qualifications.
Kingston upon Thames: the February 2024 validation list, adopted on 1 May 2024, says all applications involving basement development require a Basement Impact Assessment signed by a Chartered Civil Engineer or Chartered Structural Engineer. Use the Party Wall surveyors for Kingston upon Thames properties guide for the current-plan and validation position.
Merton: adopted Policy D12.11 requires four documents with every basement or subterranean development application: a Basement Impact Assessment, Drainage Strategy, outline Construction Method Statement and Construction Traffic Management Plan. The adopted Local Plan also prohibits new basements beneath the public highway. The Party Wall surveyors for Merton properties guide separately corrects the council SPD’s incomplete section 6 shorthand.
Richmond upon Thames: the Local Plan adopted on 7 October 2025 replaced the 2018 plan. Policy 54 resists more than one basement storey at residential properties and applies garden, structural, groundwater, drainage and construction controls. Two basement Article 4 directions together cover the borough, so the basement development described by them has required planning permission since 1 April 2018. See Party Wall surveyors for Richmond upon Thames properties.
Sutton: the 2018 Local Plan remains adopted. The Regulation 19 replacement completed consultation on 31 July 2026 but was not adopted on 24 August, so its proposed dedicated basement policy is not current policy. The council still lists a 2006 residential-extension SPD; its dimensions are old adopted planning guidance, not a Party Wall test. The Party Wall surveyors for Sutton properties guide preserves those status boundaries.
Wandsworth: the current adopted-plan page confirms that the March 2026 Partial Review superseded only six named policies, leaving basement Policy LP6 in force. LP6 permits no more than one storey of basement accommodation, applies a maximum 50% garden test and requires at least one metre of naturally draining permeable soil plus a 200mm drainage layer over a garden basement. The Party Wall surveyors for Wandsworth properties guide separates those planning controls from the Act.

The strictest planning submission pack does not prove that Party Wall notice is required. The absence of a borough basement policy does not prove that notice is unnecessary. Planning, building control and the Act answer different questions.

Preserve every part of the statutory tests

Use the Party Wall etc. Act 1996, not a council summary, to classify the proposed work.

Section 1: this is not a universal boundary-work rule. The gateway concerns differently owned adjoining lands where the line of junction is unbuilt or has only the qualifying boundary wall described by section 1. If the section applies and an owner is about to build on the line, the notice period is at least one month. Without the adjoining owner’s consent to build astride it, the statutory alternative is a wall wholly on the building owner’s land and at that owner’s expense.
Sections 2 and 3: before exercising any right conferred by section 2, the building owner ordinarily serves a party structure notice at least two months before the intended start. Section 3(3) preserves two exceptions: a section 2 right exercised with the written consent of adjoining owners and adjoining occupiers, and work required by a statutory notice concerning a dangerous or neglected structure.
Section 6(1): the proposal must be to excavate, or excavate for and erect a building or structure, within three metres horizontally of part of an adjoining building or structure, and part of the proposed work inside those three metres must extend below the level of the bottom of the adjoining foundations.
Section 6(2): within six metres, ask whether any part of the proposed excavation, building or structure would meet the statutory plane. Section 6 draws it downwards in the direction of the building owner’s excavation, building or structure at 45 degrees to the horizontal. Its origin is the line where the horizontal plane at the adjoining foundation-bottom level meets the plane of the external face of the adjoining building’s or structure’s external wall.

Where section 6 applies, notice must be served at least one month before beginning to excavate, or excavate for and erect. It must state whether underpinning or other safeguarding is proposed and be accompanied by plans and sections showing the excavation site and depth and, if a building or structure is proposed, its site. A planning 45-degree daylight line is not the section 6 foundation plane.

Build an address-specific review file

For a south-west London property, assemble:

the full address and verified local planning authority;
the title plan and the ownership position at the line of junction;
existing and proposed drawings identifying every shared wall, floor, ceiling and boundary structure;
excavation sections showing horizontal distances, formation levels and the known or unknown bottom of adjoining foundations;
the current adopted plan, validation list and any address-specific Article 4, conservation or flood result;
the BIA, drainage, structural and construction-management material required by the relevant authority;
every notice, response, drawing and item of correspondence already exchanged; and
the intended start date and any access or sequencing constraints.

Record unknown foundation information as unknown. Do not convert an assumed depth, an estate-agent locality or a postcode into a statutory conclusion. If professional advice is obtained, check whether it covers planning documents, notice validity, adjoining interests, inspections, a schedule of condition, an award and later stages rather than assuming all are included.

Sources checked

The six-borough scope, adopted-versus-emerging plan status and basement controls were checked against the linked NHS and council sources on 24 August 2026. The statutory summary was checked against sections 1, 2, 3 and 6 of the Party Wall etc. Act 1996 and the GOV.UK explanatory booklet. The booklet is general guidance, not a binding interpretation or case-specific legal opinion. Recheck the exact address and current documents when the work is prepared.