Overview

Delta registered installer T W Read Waterproofing Ltd has extensive experience in providing professional design and installation of waterproofing systems for existing and new-build structures.

The scope of this project was to provide a structural waterproofing solution to a large basement that had been formed below a residency in Streatham, South-West London. These works were originally undertaken by a basement company who had ceased trading. Whilst the excavation works had been completed, no waterproofing system had been installed. The structure was a build from the 1890-1900 era; usually urban houses of this vintage were well-built and have few structural problems. The basement consisted of two apartments with two lightwells and a large courtyard to the rear. At the rear of the property there was also a podium deck that required waterproofing.

Working in collaboration with the architects, T W Read Waterproofing Ltd was easily able to offer a simplistic and practical approach. Based on the assessed risk and performance level requirements for the basement – grade 3 in accordance with BS 8102:2009 - two forms of structural waterproofing would be required.

Type A waterproofing

Type A is defined as ‘barrier protection’ which physically holds water back on either the positive side of a below ground level structure (externally), the negative sides (internally), or sandwiched into the construction. Cementitious coatings, bituminous coatings or flexible sheet membranes are categorised within Type A ‘barrier protection’.

Type C waterproofing

Type C is defined as “drained protection”. A drained cavity system collects and manages any moisture which breaches the integrity of the structure by channelling, collecting and discharging such free water via a suitable evacuation point. A Type C waterproofing system will not increase or exert water pressure on a structure nor alter the dynamics.

Initially all efflorescence/salts on the surface of the walls were removed via wire brush prior to the application of Polysil TG 500, all construction and dry pack joints were sealed using Koster Repair Mortar Plus. In a full belts and bridges approach, T W Read Waterproofing Ltd applied a closed layer of Koster NB 1 sealing slurry to prevent migratory dampness to the light wells, basement, and courtyard.

Delta MS 500 was securely fixed to the internal walls of the basement using Delta’s specialist fixing plugs, with Delta MS20 installed to floors.

Delta’s pump partners, Package Pump Systems Limited (PPS) designed a bespoke basement drainage solution with pumping stations for the ground and foul water.

After the Type C system was installed the all-important integrity testing was undertaken to exercise the waterproofing system in worst case scenario.

Products used

  • Delta MS20
  • Delta MS 500
  • Delta Channel and Channel components
  • Koster NB 1 Grey
  • Koster Polysil TG 500
  • Koster Repair Mortar Plus
  • Delta Bespoke submersible pump stations

Outcome

A completely watertight solution was provided with works carried out to a high standard and delivered on time.

As a particularly experienced Delta registered installer, T W Read Waterproofing Ltd was able to confidently recommend, design and install a comprehensive waterproofing system that will protect the property from unwanted water ingress for the life-cycle of the structure, much to the delight of the client.