Replacing Failed Deck Waterproofing at Gunwharf Quays, Portsmouth

Summary

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  The deck area to be waterproofed was separated into bays

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  Drainage ports between bays also required careful attention

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  Proper membrane detailing was required at the corners

Gunwharf Quays, Portsmouth

Gunwharf Quays has been the prominent and premier retail destination on the South Coast since it opened in February 2001. The major outlet houses over 90 brands in the heart of the historic maritime city of Portsmouth. The waterside location sits directly alongside Portsmouth Harbour, with views of the iconic Spinnaker Tower.

Project Scope

During planned structural alterations to expand the area, principal contractor Conamar removed existing flooring to expose the previously failed deck waterproofing system.

An area of 240m2 of concrete deck was exposed over an underground car park. The existing waterproofing had deteriorated and was no longer fit for purpose, presenting a significant risk of water ingress onto vehicles and damage to the below-ground structure.

Conamar therefore approached us to provide a remedial waterproofing solution, in partnership with our specialist contractor QST Construction Services.

The Solution

The experienced team at QST Construction collaborated closely with our technical experts to specify a complete beam & block deck waterproofing system, and to ensure that the correct installation method was followed from the outset.

Firstly, QST ensured that the area was prepared for a new waterproofing system by:

• removing all existing failed waterproofing materials
• mechanically preparing the substrate to remove any contaminants
• ensuring its suitability for a new waterproofing system

This comprehensive approach ensured that QST were then ready to install our specialist, BBA approved deck waterproofing system, PolyMaxx HA.

PolyMaxx HA is a seamless, hand-applied, fibre-reinforced membrane system designed for use on decks, flat roofs, protected and unprotected balconies, and walkways.

The advanced curing technology means each coat typically cures within 30 minutes, allowing the full system to be installed in a single working day. The result is a flexible, durable membrane that is fully bonded to the substrate, effectively preventing water tracking.

Replacing Failed Deck Waterproofing

Specifying a high-quality deck waterproofing system such as PolyMaxx HA, installed by specialist trained contractors like QST Construction, allows for the installation of a seamless, reinforced waterproof barrier that completely protects exposed or covered decks from water ingress.

QST did have some challenges to overcome, however. These included a working area with no weather protection, a winter installation, and persistent water ingress at perimeter edges that required additional detailing.

The Result

Testing the system with a successful 80mm flood test

Despite the winter weather, the installation progressed quickly and smoothly on this prestigious site. Thanks to their thorough preparation and precise installation, QST effectively waterproofed all areas of the concrete deck with the PolyMaxx HA System. This was verified by a 36-hour flood-test at a depth of 80mm, with no leaks detected.

Testimonial

“The PolyMax HA system proved to be highly user-friendly, allowing efficient and consistent application. When conditions allowed, works advanced smoothly and to a high standard.”

Bradley Hartley, Project Manager
QST Construction Services