Planning is a legal procedure to which standard questions are applied. Croft Structural + Civil has developed and continues to evolve its documents to ensure that they meet the Council’s planning requirements. Hammersmith and Fulham Council require that, at planning, all Basement construction complies with their Development Management Development Plan Document (DM DPD), and follows the guidance contained in Planning Guidance Supplementary Planning Document, July 2013. Policies relevant to basement construction include SPD Housing Policy 9 Basements, SPD Design Policy 12 Assessment of Proposals for Lightwells and Basement Excavation.

SPD Design Policy 13

The Policy stipulates that the basement should:

(i) not increase the risk of flooding from any source and in areas that are at medium to high risk of fluvial flooding, there must be a satisfactory means of escape in the event of a flood;

(ii) meet the policies and guidance for new lightwells;

(iii) meet the guidance set out in the Building Research Establishment’s (BRE) report ‘site layout planning for daylight and sunlight – a guide to good practice’ and the provision of daylight and sunlight to rooms is adequate;

(iv) meet the minimum requirements for the net floor area of the flat and net floor area of individual rooms set out under SPD housing Policy 5; and

(v) be in accordance with on or off-street parking requirements set out in the Transport SPD, if an additional residential unit is being created; and

(vi) include a Subterranean Construction Method Statement (carried out by a qualified structural surveyor or civil engineer) and submitted with the planning application and made available to neighbouring owners

(vii) provide active drainage devices to minimise the risk of sewer flooding

(viii) the contaminated land search where necessary

Croft Structural + Civil’s Basement Construction Method Statements

Croft Structural + Civil’s Basement Construction Method Statements is completed in accordance with the guidance of the DM DPD and the relevant Supplementary Planning Documents (SPDs). These form part of Hammersmith and Fulham’s Local Development Framework (LDF). This Subterranean Construction Method Statement is a systematic check through various potential impacts to allow the town planners to make an informed decision of the basement proposals.

Croft Structural + Civil provides this service which covers:

Site Inspection

  • Meeting with an engineer to discuss the needs of the projects and specific requirements
  • Walk over survey to determine what the requirements of the site are
  • Review of adjacent buildings where access is available
  • Are there signs of subsidence locally

Desk Study

This forms the bulk of the Basement Construction Method Statement and will includes but is not limited to:

  • Structural Schemes of internal layouts
  • Proposed use and loadings
  • Retaining wall designs
  • Anticipated deflections of retaining walls
  • Local Stability
  • Construction Process with specific information regarding the excavation, temporary works and construction techniques
  • Flood Risk Assessment – where applicable

Hammersmith and Fulham require that the Subterranean Construction Method Statement is prepared and signed off by a Chartered Civil Engineer (MICE) or Structural Engineer (MIStructE). Our engineers at Croft have the qualifications for this requirement.


At the end of 2020 H&F approved a basement plan for a basement which was close to an old bus depot. The basement suffered from Petrol Chemical Gas intrusion and the council was sued. The requirements for gas monitoring and contamination have slowly been increased for H&F at planning. For a  council which approved CMS without a physical soil investigation they are now requiring an in-depth gas and chemical monitoring on many sites.