Archive for June, 2016

Triton supplies Type C waterproofing for landmark London scheme

Thursday, June 23rd, 2016

The White Collar Factory will be a mixed-use area of workspace, residential and retail, designed by architects, AHMM.  The development, sited on London’s City Road, comprises a new 16-storey office tower, a new public square and refurbished existing buildings to the rear.

The new 2-storey basement has been waterproofed using a Type C system applied internally, to provide drained protection in accordance with BS 8102: 2009. The waterproofing system has been supplied by Triton Systems.

During demolition of the existing structure, the sub-contractor (Dunne Group) worked closely with Triton’s CSSW qualified technical team, to design the most appropriate and cost effective waterproofing system that was subsequently approved by all relevant parties as the most suitable protection against potential ground water ingress.  2,000 m2 of Platon P20 cavity drain membrane was subsequently specified for all earth retaining basement walls on both levels and the ground bearing slab at lower level.  BBA certified Platon P20 membrane is a high capacity drainage membrane recommended for use where it is important to significantly reduce the risk of blockages behind the membrane caused by lime deposits.

Prior to the installation of the membrane, all fresh concrete at earth retaining elevations was treated with Triton’s Anti Lime solution. This treatment hardens and dust proofs the concrete as well as locks in free lime to further reduce the risk of blockages in the drainage elements of the system.

Any water entering the construction at upper and intermediate basement levels is gravity drained behind the studded P20 membrane down to a waterproof concrete bund/upstand which provides a 100mm cavity, onto which internal block walls can be built.

A series of 40mm holes at 900mm centres were drilled within the bund to allow any water to drain down behind the membrane installed to the walls at lower level. The bund was also waterproofed with Triton’s cold liquid applied TT Vapour Membrane (TTVM) that will prevent potential damp patches being visible on the internal block wall faces. A band of TTVM was also applied around the perimeter of the lower soffit dressing down behind the P20 membrane installed to the external walls and sealed with Triton Corner Strip (butyl tape).

Bunded detail

In line with the requirements of BS 8102: 2009, removable panels were installed in the bund to allow access to flushing ports. These allow the system to be regularly maintained and flushed through to ensure a clear passage of water is maintained to the sump/pumps that are set within the lower floor slab.

Vertical joints in the Platon P20 were sealed using Platon Sealing Rope and Brick Plugs, with all wall/ floor junctions sealed using Platon Corner Strip Tape – a wider waterproof butyl tape. Platon Sealing Rope was used to seal joints in the P20 membrane that was loose laid to the floor slab.

Water draining from the system to the lower floor slab is drained via gulleys in the slab to the installed sumps. These gulleys also incorporate rodding eyes at approximately 12LM intervals to allow for maintenance of the system.

The P20 membrane on the floor has been screeded over ready to accept finishes and the construction of internal walls.

Triton systems specified for underground car park upgrade

Thursday, June 16th, 2016

Triton Systems supplied waterproofing systems specified by waterproofing design specialists, Ink Technical Services, for the upgrade to a below ground car park in North London.  BS 8102 (2009) recommends the involvement of a waterproofing specialist at the design stage of any waterproofing project. Involving an expert at this stage also minimises the risk of system failure in the future.

INK’s initial inspection revealed a reinforced concrete construction with a surface water drainage system in a poor state of repair. There was water seepage from cracks in the floor and from the wall/floor joints. Much of the floor was badly stained with oil.

Taking into account the intended use of the area as a car park below a residential block, and an unknown water table classification, INK recommended a ‘Type C’ drained waterproofing system (as defined in BS 8102: 2009) for the perimeter walls and a ‘Type A’ barrier protection system to the floors. The Type C system would comprise a new concrete upstand to maintain the structural integrity at the perimeter wall/floor junction and to provide the required perimeter drainage channel detail.  The recommendation included the waterproofing of the upstand using shrink compensated mortar at internal and external floor angles and a cementitious ‘tanking’ slurry. The INK design also stipulated that rodding points were incorporated to the drainage channel and the system tested prior to installation of the membranes.

Concrete upstand created to form gulley for Aqua Channel for perimeter cavity drain membrane system

The wall/soffit angles at the perimeter of the basement should also be waterproofed with shrink compensated mortar and a one metre band of tanking slurry installed around the perimeter of the soffit to which the top of the 8mm studded cavity drain membrane could be sealed using a special membrane sealing strip.

To minimise damage to the walls by cars INK also advised the installation of a suitable concrete block wall, tied back to the external wall using special membrane ties.  The design also recommended an additional 300mm ‘condensation’ strip of the 8mm membrane to be installed to the base of the block wall facing the membrane, to minimise the risk of condensation in the cavity.  It also included the installation of vent grills in the block wall to give access to the rodding eyes of the perimeter drainage channel.

Triton TT55 detail to soffit linked in behind Platon P8 membrane for water to drain down into gulley, prior to installation of Aqua Channel and sealing upstand with TT55

INK also recommended the existing sump and pumps were fully serviced as part of the upgrade and a mains/battery high level alarm incorporated as a minimum requirement. Ideally this would be a telemetric system enabling remote alert to any potential issues. A 12 monthly service schedule will also be put in place to maintain the pumps and drainage system to be carried out by the installing contractor or suitable specialist.

The recommended two-component epoxy coating for the floor would provide Type A waterproofing, with the second coat incorporating an anti-slip grit.   Prior to the coating being applied, the floor was to be cleaned and all cracks repaired with a suitable waterproofing plugging compound.

The INK team was satisfied that providing the above design was installed by a specialist contractor, a Grade 2 environment would be achieved for the residents. This ‘level of dryness’, according to the British Standard, is one that tolerates moisture vapour but no water penetration and is the typical Grade required for car parks and retail storage areas.

Car park before upgrade