Basement Waterproofing – Lansdowne House
Introduction
Lansdowne House, an ambitious redevelopment led by Allford Hall Monaghan Morris (AHMM), features extensive basement levels designed to accommodate plant rooms, amenities, and critical infrastructure for the building. With subterranean structures comes the challenge of managing groundwater and ensuring long-term structural integrity.
Total Specialist Maintenance (TSM) was appointed to deliver a robust, maintainable waterproofing solution across basement levels B2 (double height) and B1. The scope included installation of Delta MS500 cavity drain membrane to basement walls, MS20 to concrete slabs, and a maintainable drainage channel system protecting wall–floor junctions.
Working within a tight construction programme on a complex, high-profile development, TSM delivered a high-performance waterproofing system designed to control moisture, manage hydrostatic pressure, and provide long-term resilience for the structure.
The Challenge
The basement areas at Lansdowne House presented several project-specific challenges:
- Large double-height B2 basement: Required the installation of high-level membranes at significant working heights, demanding precision and rigorous safety control.
- Structural complexity: Multiple interfaces, penetrations, and transitions across wall and slab areas needed consistent detailing to maintain system continuity.
- Tight programme: TSM operated within a demanding schedule, coordinating with multiple trades to avoid disruption to ongoing structural and fit-out works.
- Long-term maintainability: The client required a solution enabling future access for drainage maintenance without compromising building operations.
The Importance of Basement Waterproofing
Effective waterproofing in deep basement structures is critical for:
- Preventing water ingress that could damage interior finishes and services
- Minimising risk of mould, damp, and structural deterioration
- Protecting the mechanical and electrical systems often housed in basement levels
- Reducing long-term maintenance costs and ensuring compliance with BS 8102 guidance
TSM’s installation of a fully maintainable cavity drain system ensured that any water entering the structure is controlled, collected, and safely diverted, protecting the basement for the lifetime of the building.
The Solution
TSM delivered a full waterproofing package using Delta Membrane Systems components, installed in sequenced phases to achieve performance continuity.
- Installation of Delta MS500 to Basement Walls (B1 & B2)
A 8mm high-density polyethylene cavity drain membrane (MS500) was mechanically fixed to the internal face of basement retaining walls. This created a controlled drainage cavity capable of managing moisture and directing it to perimeter channels. - Maintainable Drainage Channels at Wall/Floor Junctions TSM installed Delta’s maintainable perimeter channel system, ensuring continuous water collection around the entire basement footprint. Access ports were integrated to allow future maintenance and inspection, supporting long-term reliability.
- Delta MS20 Applied to Concrete Slabs
A 20mm cavity membrane (MS20) was laid across the basement slabs, offering enhanced drainage capacity and providing a robust interface for subsequent floor build-ups. This system is designed to manage significant hydrostatic pressures while maintaining full serviceability. - Coordination and Sequencing
Installation was coordinated with structural and MEP trades to ensure uninterrupted progress despite programme constraints. Attention to detailing at corners, joints, and penetrations guaranteed system integrity across all areas.
Handling Project Complexities
Working at Height in Double-Height Basement
Level B2’s double-height design required precise installation using mobile access equipment. TSM operatives adhered to strict safety protocols to maintain productivity without compromising safety.
Ensuring System Continuity Across Multiple Interfaces
TSM’s technical knowledge ensured proper treatment of construction joints, kickers, penetrations, insulation interfaces, and transitions between wall and floor systems.
Programme Management
Daily coordination with main contractors ensured all works progressed within the tight programme, demonstrating TSM’s capability to deliver specialist works on major developments without delay.
Quality Control
Inspection of membrane fixings, channel gradients, and water management routes guaranteed the entire system met Delta installation standards.
Environmental Considerations
The Delta cavity drain system offers several environmental advantages:
- Low-waste installation process with minimal use of wet trades
- Non-destructive waterproofing method, preserving existing structural elements
- Fully maintainable system, extending service life and reducing future material usage
- Non-toxic membrane materials, ensuring safe use within occupied buildings
These qualities make the system suitable for environmentally conscious developments such as Lansdowne House.
Project Outcome
TSM successfully delivered a fully maintainable cavity drain waterproofing system across basement levels B1 and B2. Post-installation inspections confirmed:
- Complete continuity of MS500 and MS20 membranes across all treated areas
- Fully maintainable drainage channels installed to manufacturer specifications
- A dry, controlled basement environment ready for follow-on trades
- Works delivered within the tight programme without disruption
TSM’s involvement contributed significantly to the long-term protection and resilience of the Lansdowne House basement structure. The installed system now provides a reliable barrier against groundwater ingress and ensures the basement areas remain dry, safe, and functional for years to come.
For more information on TSM’s waterproofing and specialist construction services, visit www.totalsm.co.uk.
