A basement programme needs to cover investigation and approvals as well as construction. The duration depends on the existing building, ground and water conditions, engineering method and required technical submissions, so a quoted number of weeks on site is not the same as the time from first drawings to usable rooms. [1] [2]
Plan the work in dependencies
Ask for a programme that identifies what each stage needs before it can start. For a basement, that usually means coordinating the design evidence, relevant permissions, site arrangements and the construction method rather than treating them as independent tasks. The client and appointed dutyholders need suitable time and resources to achieve compliance. [3]
A useful programme distinguishes investigation, planning, technical design, pre-start matters, structural construction and completion. The order and timing need to reflect the particular project and its outstanding decisions.
Planning time is only one part
For a non-major planning application, the usual statutory determination period is eight weeks from a valid application, unless an extension is agreed. That is not a guarantee of approval and does not include all preparation time before the application becomes valid. [4]
Where a BIA and independent audit are required, allow for preparing the evidence and answering technical questions. Camden's process specifically involves engineering input and independent checking, so an incomplete first report should not be treated as a completed planning task. [1]
Identify the pre-start conditions
Relevant construction management plans may need approval before work begins. Kensington & Chelsea's code process links its documents to planning conditions, while Westminster's revised code has applied to new sites since 1 June 2026 and existing sites since 1 September 2026. Check the requirements affecting the actual project. [5] [6]
Party wall notices also need their own programme: excavation notices generally require at least one month and party-structure notices two months. A dispute or an unresolved technical proposal can mean that expiry of a notice period alone is not the point at which work can lawfully proceed. [7]
Construction follows the engineered sequence
Underpinning, temporary support and excavation should progress in accordance with the designed method and required checks. They are not stages to compress simply because the fit-out date is approaching. HSE and the underpinning good-practice guidance emphasise the stability of the changing structure throughout the work. [8] [9]
Include inspections before work is concealed. LABC's underpinning guidance identifies inspection before concrete is placed, which must be accommodated in the contractor's programme. [10]
Finish means more than excavation complete
Allow for waterproofing, drainage, ventilation, services, internal finishes and the required testing and completion information. The waterproofing system's commissioning and maintenance arrangements need to be established before the room is handed over for use. [11] [12] [13]
Ask the contractor's programme to distinguish structural completion, readiness for finishes and final handover. This is a practical way to avoid treating an empty concrete enclosure as a completed habitable basement.
Ask for a project-specific range
Request the expected programme, the assumptions behind it and the risks that could change it. The written contract should explain the agreed timing and treatment of delays. Record the prerequisites against the proposed start date, especially unresolved design, permissions and investigations. This makes the programme's assumptions visible before you rely on a completion date. [14]