Basement Waterproofing & Repurpose – Covent Garden

The Outline: works undertaken was to repurpose an old theatre ticket office, providing a modern, habitable workspace and a new lease of life; this commercial development was in the heart of Covent Garden, London. The location required good logistics and planning by our office staff to facilitate the offloading of materials, tools and subsequent removal of waste materials for the appropriate disposal method at our premises.

Whilst the daily journey, parking permits and access proved demanding, we did benefit from some prime, top location advertising with our van outside one of the busiest tube stations in London.

The approach to waterproofing, in this instance, was based on membrane tanking, compliant with BS8102:2009 Type C. This permits the continued ingress of water through walls and floors with the resulting discharge of water from the building via channelling and pumps. Such Type C membrane solutions prevent any additional stress to weak environments that are subject to high hydrostatic pressures.

Setting Up: covered protection of access path from dust, materials and builder boots, clearance of obstructions within the work area and safe storage of materials and tools. Installation of lighting for works and safety barriers for protection where needed

Preparation to works: to ensure the substrate of walls and floor were readied to provide a clean, stable and suitable platform to apply membrane and other waterproofing treatment;

• Removal of any loose, friable and organic materials from the walls and vaulted areas, this is essential to mitigate for any blockages to the drainage being provisioned
• Removal of any sharp protrusions and fittings to substrate being membraned, puncture wounds are costly and avoided with a thorough inspection and due diligence
• Repairing any frailties with the floor (i.e blown screed, holes) in order to apply a well-adhered waterproofing treatment

• The clients own main contractor laid new slab were required in this instance, this facilitated installation of drainage channels and then a sump and pump. It is however quite common to cut channels and sumps from the existing slab where headroom constraints require
• The necessary drainage channels from the perimeter were installed and connected the sump pump
• A remote Aqua Pump alarm system was fitted and checked during the all-important flood testing of the system

• The clients own main contractor laid new slab were required in this instance, this facilitated installation of drainage channels and then a sump and pump. It is however quite common to cut channels and sumps from the existing slab where headroom constraints require
• The necessary drainage channels from the perimeter were installed and connected the sump pump
• A remote Aqua Pump alarm system was fitted and checked during the all-important flood testing of the system

With all the pre-requisites handled and approval of our Work Manager, the task of sealing the structure from dampness could begin.

Waterproofing the Walls and Vaults: encompassed the fitting of 8mm polypropelene membrane using task-specific waterproof plugs. The plugs include built-in screw cavities to permit perfect screwing of timber battens to the dry side of the installation.

Once positioned, any deliberate overlaps of the membrane are then taped and sealed using specific materials provided by the membrane manufacturer; existing/remaining services were worked around as is common practice.

The contours of this basement with its vaulted ceilings and arched doorway required a dedicated and diligent approach to cutting and sealing in order to ensure a thorough watertight lining.