Context

The new 3-storey basement being created at the Victoria and Albert Museum in London will include a purpose-built subterranean gallery for temporary exhibitions to showcase the best of contemporary design.

Effective structural waterproofing is a key requirement for the project.

Work undertaken

A variety of waterproofing materials and systems were chosen from Delta Membrane Systems range. Wates Construction appointed VolkerLaser (a company that has used the Delta range on many occasions) to carry out the waterproofing work.

Waterproofing the external structure of the basement

The external structure for the basement was created using contiguous piling, faced up with sprayed waterproof concrete.

The internal facing is coated with Köster Polysil TG500 – a thin anti-lime fluid based on a polymer and silicate combination. Polysil TG500 helps reduce the pore volume and reduce the danger of new development of salt efflorescence and free lime egress. It also increases the chemical and mechanical resistance of mineral building materials. Capable of penetrating the substrate by up to 20mm, Köster Polysil TG500 also has strengthening and hydrophobic properties. It is compatible with mortars, plasters, cementitious slurries and concrete.

Waterproofing the basement walls and floors

Many of the wall areas in the building are waterproofed using the Delta MS500 wall membrane which drains any water or water vapour that may ingress through the structure to a suitable drainage outlet.

The floor slab are waterproofed using the Delta MS20 floor membrane. This heavy gauge option has 20mm deep studs to give extra drainage capacity. Features include a compressive strength of round 200kN / m2, with excellent pressure distribution and low point loads.

Other internal walls within the structure are coated with Köster NB1 slurry which is a mineral coating containing crystallising and capillary plugging agents. Köster NB1 can be used for waterproofing against ground moisture, non-pressurised and pressurised water. Waterproofing undertaken with Köster NB1 slurry is characterised by excellent resistance to pressure and abrasion as well as excellent resistance to chemicals. Areas that are coated with NB1 slurry also benefit from bentonite sheeting on the outside of the piling in areas.

System Components

  • Delta MS500 wall membrane.
  • Delta MS20 floor membrane.
  • QwikSeal fixing plugs.
  • Double-sided tape.
  • Delta corner strip tape.
  • Delta drainage channel.
  • Koster Polysil TG500.
  • Deep penetrating primer for damp, salt-containing substrates and an anti-lime treatment for new concrete. Also a liquid hardener for sealing slurries.
  • Koster NB 1 grey slurry.
  • Mineral waterproofing slurry system for sealing against pressurised water.