Flag success re-roofing Clissold Leisure Centre
Comment on Flag Soprema’s involvement in one of the most demanding roofing specifications of the last 25 years.
Figures for the ultimate cost of the London Borough of Hackney’s notorious Clissold Leisure Centre vary. Up to £50 million has been quoted (though £34 million seems a more realistic estimate) for a project that was to be guaranteed media exposure with every new piece of speculation and bad news that came to light.
Examining how long-term waterproofing protection could be provided following the roof’s failure, Flag Soprema UK’s Flagon SV and SFc reinforced PVC single ply membranes were specified for the complex, new 2000m2 insulated flat roof.
Despite £10 million of Lottery funding prompted by Sport England, the original roof had leaked every time it rained and the building’s ventilation was clearly not up to the task. It was described as "…the wrong building at the wrong time in the wrong place" and ‘the swimming pool that sank’. All this after such an outwardly promising start when the centre was included as “a model of the future leisure centre” on a world tour in the ‘12 for 2000: Building the Millennium’ exhibition'. With the British Council as curator, politicians were falling over themselves to release sound bites in its praise. No less than Culture Secretary Chris Smith cited it as "… a reflection of the UK on the verge of the 21st century". However, a report in ‘Building’ magazine as early as 1999 hinted at what was to follow, saying "The main staircase, where stairs and landings are all cantilevered off a slim 400mm-thick central wall is a key example of structure working at the edge of tolerance”. Among the catalogue of construction problems, however, the biggest by far was the roof, which leaked across almost its entire span. The site team's real problems started when the concrete frame and the steel spine girder running the length of the building had been installed. The roof trusses and panels were all to be hung from it, creating a series of deflections that ultimately defeated the engineers' and contractors' pre-planning, and overran the time allowed for installation in the construction programme.
After closure in 2003, for what was ultimately to be over 4 years, Hackney Council stated that it was expecting the worst following commissioning of consulting architects Bickerdike Allen Partners with engineer Arup in the capacity of expert witness. By the end of 2004, it was saying that Clissold faced the bulldozer, hardly surprising given confirmation of 59 serious safety defects. Bickerdike Allen identified "complex and serious defects throughout the building". These included many examples of incorrect detailing which resulted in newly appointed contractor Wates Construction having to install a new roof. Involvement of a new waterproofing membrane manufacturer was also required given the failure of the original construction. Repairs cost £11.5 million, with an additional £1.5 million spent on additional improvements.
Flag Soprema Sales Director Steve Greaves commented “The new roof at Clissold presented technical challenges which enabled us to confirm the company’s willingness to provide specifications for the most exacting roofing projects. Many expected the Centre never to open again, but the roof’s performance has fully justified faith shown in our system and the contracting standards which supported it. It is a perfect example of how fully trained, approved contractors who are monitored on site during installation can produce the exceptional standards of workmanship that we demand. Our 'Partner Training Academy' focuses on the training needs of the designer and main contractor and the benefits of such an approach are clear for all to see in this case”.
The Flagon SV and SFc membranes used in the Clissold project are adaptable to structural movements, are resistant to static and dynamic puncturing, have high tensile strength and not susceptible to dimensional shrinkage. Specialist roofing contractor M.A.R.S. (Construction) Ltd was employed to undertake installation, which involved the greater part of the membrane fully adhered and the remainder mechanically fixed. The roof will continue to be the subject of regular inspection as part of the guarantee requirements.