Overview

The scope of this project was to facilitate a combined waterproofing solution for a 2,000m² luxurious subterranean space which includes a double-level basement that will accommodate a cinema room, spa wing and swimming pool, changing and screening rooms, servery, storage and laundry wing, plant rooms and other accommodation.

Delta registered installer Knowles was appointed as principal contactor to collaborate with the architects to fulfil the role of Waterproofing Design Specialists in providing a reliable, watertight solution for this £100m project.

Knowles created a combination waterproofing design which was compliant with British Standard 8102:2009 2009 ‘Code of Practice for Protection of Below Ground Structures Against Water from the Ground’.

The project required Grade 3 protection – no dampness or water penetration was acceptable.

Methodology

In addition to the Type A and C waterproofing systems, Knowles used Delta's new (Type B) watertight concrete additive, Koster BDM which had previously been used in Europe and extensively in other countries. Koster BDM is a crystallising integral waterproofing additive for concrete and was supplied for a volume of 3000m³ of waterproof concrete poured over a period of 12 months. The tallest walls were required at 6.750x0.5m thick, with the largest spanning slab 10,700m².

Prior to the pour of the concrete slab, Delta DualProof was utilised. DualProof is a pre-applied fully and permanently bonded composite sheet waterproofing membrane. It consists of a special non-woven Fibre-Tex fleece co-extruded with a highly flexible PVC membrane designed for use with structural reinforced concrete. Freshly poured concrete is embedded completely into the specially designed and developed fleece, creating a unique and permanent mechanical bond.

Delta’s Type C system was used internally, providing negative side waterproofing.

Prior to the installation of the Type C system, all new concrete was treated with Koster Polysil TG 500 to prevent the leaching of free lime, with all construction joints sealed using Koster Repair Mortar Plus. Knowles applied a closed layer of Koster NB 1 sealing slurry to prevent migratory dampness.

Delta products used in conjunction with Knowles expertise included:

  • Delta MS20
  • Delta MS 500
  • Delta Geo-Drain Quattro
  • Koster Deuxan 2C
  • Delta DualProof
  • Delta Drainage channels and connectors
  • Koster NB 1 Grey
  • Koster SB Bonding Emulsion

Outcome

Delta’s site services team delivering an exceptional quality assurance and training service throughout.

Knowles provided a complete bespoke watertight solution following the guidelines set out in BS 8102:2009, with all works undertaken to a high standard and delivered on time, despite changes to the waterproofing design.