The Latest Luxury
Stirling Lloyd’s advanced waterproofing systems are currently being used at Barratt Homes’ ‘Great West Quarter’ (GWQ) development. When complete in 2011, GWQ will be a truly aspirational place to live. The three acre Chiswick site will create a new community consisting of 1,040 apartments for both private and social housing, various green spaces, a luxury hotel, retail areas, an art gallery and numerous eateries, cafés and wine bars. At the centre of the brownfield site will be the main piazza – providing a lush green space for recreation and relaxation, while running through the piazza will be a bus service linking the development to central London. To complement the high specification of the development Barratt’s required effective, high performance waterproofing solutions to give complete and effective protection against the harmful effects of water and other corrosive elements.
A Podium To Be Proud Of
The piazza sits on a concrete podium deck with underground parking below so a reliable and robust waterproofing solution was required to protect this vital element of the development. To be populated by pedestrians, cars, buses and cyclists once complete the podium waterproofing needs to retain its integrity over the long term, while in the short term the deck is being used by site traffic and so the system chosen needed to be resilient enough to withstand heavy plant and equipment. Stirling Lloyd’s tough, BBA approved Integritank system, which is based on advanced methyl methacrylate (MMA) resins, more than met this criteria.
In addition, not only are there large areas to be coated at GWQ, but also the work needs to be carried out in several phases. Spray applied, Integritank gives large daily outputs while its ability to bond to itself with “no critical overcoating time” enables phasing of works and ensures complete, seamless coverage with no vulnerable day joints.
These qualities combined with Barratt’s positive experiences with the product, which dates back to 1997, when Integritank® was used at the companies Hermitage Waterside Development to protect the balconies, planters and podium deck led to the specification of the Integritank system.
The contract to install the system was awarded to Stirling Lloyd Construction, part of the Stirling Lloyd Group. Once on site, the substrate is prepared by captive blasting and tensile adhesion tests are carried out to confirm that the minimum specified adhesion values between the substrate and the membrane of 0.3N/mm2 would be achieved. In fact these values are being easily achieved, with the eventual mode of failure being in the substrate itself, rather than in the bond between the membrane and substrate.
The deck is then primed with MMA based PAR1 primer, which cures in under an hour. The first coat of Integritank, pigmented yellow, is then spray applied to the deck at a wet film thickness of 1.2mm; thickness tests are carried out throughout the application to confirm the specified thickness is being applied. Once cured, again in under an hour, the second coat of Integritank pigmented a contrasting grey to provide a visual aid to coverage is spray applied to the deck. Once more wet film thickness measurements are taken to confirm that the specified 1.2mm is being applied. In under an hour this second coat has cured and electrical integrity testing can be undertaken to verify that 100% effective protection has been provided, with the deck completely waterproof and also able to accept site traffic. The rapid application and speed of cure of Integritank has enabled the application team to more than meet the scheduled programme.
Forthcoming phases require further application to different sections of the podium deck, which will see a total of approximately 22,000m2 protected.
Across the podium deck there are a number of expansion joints in the concrete slab. To date 120lm of Stirling Lloyd’s Sentinel® Saba joint system has been used to treat these, which will rise to 1 ¼ km by the time the project is finished. Sentinel Saba ensures that the joints are sealed and protected against water ingress whilst allowing for the structure to move and expand. The liquid applied system is quickly and easily installed and allows for movement of up to 50mm in three dimensions. It is also fully compatible with Integritank.
The Preferred Solution
For the roofing and balcony waterproofing a hot applied, bitumen based system was initially specified; however after seeing the speed and ease of application and the robustness of Integritank on the podium deck as well as the health and safety benefits provided Barratt West London decided to use it to waterproof the balconies and roofs and Stirling Lloyd Construction were able to provide a complete installation package for all the works. On completion over 12,000m2 of Integritank will have been used on the roofs and the 2,000 balconies on the project.
As well as ensuring 100% effective protection against water penetration, the cold application removes the health and safety risks of having hot trades on site, while the simple compact spray equipment enables most areas to be treated by spray application. Even in the small areas where it was not practical to use this equipment, Stirling Lloyd were able to provide a fully compatible hand grade material.
Offering A Complete Watertight Solution
The technical support, detailing and assistance being provided by Stirling Lloyd Polychem and Stirling Lloyd Construction has meant that the works carried out on the development thus far have met the high standards expected by the Client. By offering a range of waterproofing solutions and ancillary products Stirling Lloyd have been able to provide a one stop, complete package that will give Barratt West London the greatest level of confidence in the protection of this development and their prestigious head office.
