UNDERSTANIDNG EXTERNAL DRAINAGE

How a property manages drainage is one of the first technical considerations we address at the commencement of every project. While traditional London homes frequently feature external drainage stacks, modern architectural designs often favour concealing these systems within the building footprint to achieve a cleaner, more minimalist silhouette.

When planning a refurbishment, identifying the exact location and condition of your drains is essential. This knowledge influences several critical project factors, from logistical planning to fire safety compliance.

1. Logistical and Safety Considerations

Knowing the placement of your drainage stacks allows for more accurate site preparation. For example:

• Scaffolding Requirements: External drainage works often necessitate the erection of scaffolding, which impacts both project costs and local authority pavement licences.

• Fire Safety and Internal Boxing: If drainage pipes are relocated or concealed within the interior, the "boxing" or enclosure must be properly fire-rated after connections are completed. This is vital to prevent the spread of fire between different floor compartments.

  
  

2. The Leasehold and Licence to Alter (LTA) Process

If your property is a leasehold, modifications to the drainage system cannot be carried out in isolation. You will likely be required to agree upon a specific timeframe with the freeholder for any necessary disconnections as part of your Licence to Alter.

Furthermore, in the context of a Higher-Risk Building (HRB), typically those over 18 metres or seven storeys, the regulatory burden is significantly higher. You will be expected to demonstrate in advance that the proposed drainage works will not compromise the life safety systems or the structural integrity of the rest of the building. In these instances, work must not commence on-site until a formal agreement has been received from the relevant authorities and the freeholder.

3. Beyond Basic Plumbing: The Need for Technical Oversight

There is a common assumption that appointing a competent plumber is sufficient when addressing drainage. However, as the complexities of fire rating, leasehold covenants, and high-rise safety legislation illustrate, a plumber’s expertise often does not extend to the broader architectural and legal requirements.

Professional architectural oversight ensures that your drainage strategy is integrated into the wider design while remaining fully compliant with primary legislation and building insurance requirements.

Specialist Architectural Advice

Drainage is a fundamental component of a building’s "anatomy." Addressing it with technical rigour at the design stage prevents costly remedial works and legal complications during construction.

Was this information regarding external drainage useful for your project planning? We invite you to share which other aspects of design and construction you would like us to discuss. If you require expert assistance with your current project, please reach out to our studio.