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Latest News: Underground car park dry thanks to Delta Membranes installer

Underground car park dry thanks to Delta Membranes installer

Years of leak problems at an underground car park at The Hub in Greater Manchester were ended when a Delta Membranes Registered Installer was called in to provide a robust waterproofing system.

Wet areas

The Hub is a landmark building forming an integral part of Hattersley district centre. The project was designed specifically with a “people” focus, to bring people from different backgrounds together under one roof and to supply a variety of services such as a community centre, library, youth club, police post and café.

A troublesome leaking podium deck to the entrance of The Hub had led to high volumes of water ingress to the underground parking facilities. At the time of the construction, the podium deck waterproofing system had been omitted from the original building specification. Consequently, failure occurred soon afterwards.

After several years of seeking to seal leaks and endless dye testing, The Hub called in a waterproofing design expert. Timberwise was approached to provide a guaranteed, cost effective scheme that would comply with both BS8102:2009 and any requirements of third-party warranty providers.

Underground car parks are by their very nature exposed to moisture and water ingress due to the typical environment they exist in and as a result some moisture is tolerable (Grade 1 BS8102:2009).

Following a full assessment of The Hub and its underground parking facilities it was identified that rainwater was entering the basement car park through the ceiling deck at multiple points. These points included holes that were formed to allow drainage from the surface, movement joints and investigation holes that had been created through the steel rib and concrete deck. Because of the same, there were large areas of ‘pooling’ within the basement car park.

Based on “as built plans” a system was designed post construction that would offer the same quality of structural protection had it been incorporated during the build phase.

The project commenced by removing all flagstones from the paving area to the front of The Hub and setting aside for re-use. Attention was given to the wall floor junction/fillet seals to building perimeter and inner perimeter walls. Angles are potential stress points for waterproofing systems. These crack endangered areas require special attention. Using a special expanding mortar Koster Repair Mortar Plus it is possible to transition the waterproofing products over these awkward angles without danger of the products being applied with disproportional thickness or cracking.

Furthermore, the crack bridging properties of flexible waterproofing provides security for these inherently difficult junctions.

Koster Polysil TG 500 was applied to both the junctions slab and fillet. Koster Polysil TG 500 is a free lime and salt encapsulating primer that actually modifies mineral surfaces and effectively consolidates the surface where the waterproofing is to be applied. This ensures that the waterproofing layer can bond effectively to all types of concrete, stone and brick.

An initial application of Koster Deuxan 2C was applied to the external perimeter wall and Deck. Koster Deuxan 2C provides a completely impervious layer that bonds over the whole surface removing issues associated with jointing during the installation process. A glass fibre mesh was incorporated into the first application of Koster Deuxan 2C prior to a second coat application. The combination of Deuxan 2C and Glass Fibre mesh provides crack bridging properties, the Deuxan 2C is as versatile as it is effective in providing a robust waterproofing solution.

The final stage was to overlay the Deuxan 2C with Delta Gro Drain Quattro to the external perimeter wall. Delta Geo Drain Quattro is designed to drain excess water away from a structure, offering further protection to the structure. In this instance the fabric of the building, including imbedded structural steels are now protected for the future as are the cars in the underground car park.

Delta Geo Drain Quattro is a unique four-layer drainage and protection board that also features a slip layer to further protect proprietary waterproofing systems and deal with lateral as well as vertical loads. Delta Geo Drain Quattro has a very high load-bearing capacity (400Kn per meter squared). The principle of draining water away from the waterproofing before it can pressure on it is desirable function and a good design principle which can add to the overall success of the system.

Repair work

External contractors were left to carry out the landscaping and surface water drainage connections.

Timberwise completed the project effectively and efficiently leaving the client with dry, usable underground parking facility.


Article supplied by:
Delta Membrane Systems
Tel: 01992 523 523

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