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RCI January 2018

Zink FLAT ROOFING & WATERPROOFING SYSTEMS 01992 801927 www.almhm.co.uk One of the key civil engineering structures being built as part of London’s Thameslink Programme, currently nearing completion in the capital, has been part waterproofed using a high performance membrane from Wolfin, part of the Icopal Group. Approximately 2,000 m² of the Wolfin IB PADS certified membrane were supplied direct to the London site for Yorkshirebased The roof refurbishment of the Central Building at Cambridge University’s Fitzwilliam College is one of the first major projects to use a new approach combining Sika Sarnafil’s single ply membrane with large areas of its Sikalastic 621 – a liquid applied product typically used for areas with complex detailing. This pairing of systems was further enhanced by Sika Refurbishment’s SikaFloor 420, providing a complete building envelope solution. Working closely with architect Cullinan Studio, Roofing Contractors Cambridge (RCC) and the College, Sika Sarnafil created this waterproofing solution to refurbish the roof, which has an extremely complex design. Neil Smith, area refurbishment manager at Sika Sarnafil, commented: “The original building was constructed in 1963 by famous brutalist architect, Denys Lasdun. “From ground-level you can see protruding ‘scalloped’ detailing on the roof. If you looked down on the roof from above, it is like a pictureframe, with the scallops forming the border around the edge of the flat Waterseal (W & S) in preparation to make modules on site prior to installation: a grade separation structure which isolates the lines coming in from Kent and the South Coast. As a sub-contractor to Skanska – originally awarded the Bermondsey Dive Under (BDU) and Structural Strengthening Programme (SSP) with a combined value of £75 million to design and deliver new roof. The challenge was to effectively waterproof both the flat roof – which itself had plenty of challenging details – and scalloped areas, while maintaining the look and integrity of the roof and the building as a whole.” Dave Stewart from RCC continued: “Due to the unusual shape of the scallops, it wasn’t aesthetically practical to install sheet membrane on them, so many, many discussions took place to decide how best to tackle this! “The Sikalastic product ensured these unique details would be protected without altering their shape. It’s not unusual for a project to incorporate small amounts of Sikalastic, but this is one of the first projects where the Sarnafil membrane and Sikalastic 621 have been used over large areas together. “For us, the crucial element of this 060 JANUARY 2018 RCIMAG.COM project was getting the seal right. We worked closely with Sika Sarnafil and did multiple tests to make sure the junction between the Sikalastic 621 and single ply membrane was formed using the most effective detailing. The use of Sarnametal created a strong bond between the two products, enabling them to be successfully sealed together. This was by far the most challenging part of the project, but demonstrates how well these products can work together for roofs with incredibly complex detailing.” Alex Abbey from Cullinan Studio wanted the works to be sympathetic to the original building: “We were keen to minimise weight on the roof and wanted to steer clear of asphalt and the like, so Sika Sarnafil’s lightweight products were ideal. “We needed a product that would not only effectively waterproof but that would sit over the copper scallops and maintain the shape’s detail. The Sikalastic 621 proved ideal and worked in harmony with the Sarnafil membrane. As did the SikaFloor 420, which was used on the façade and underside of the scallops – a complete solution from Sika. Importantly, the completed roof was awarded a Sarnafil Plus guarantee by Sika, a must for the client, preserving the building as an architectural landmark and study area.” http://gbr.sarnafil.sika.com Iconic brutalist gem preserved infrastructure to remove the pinch point for trains heading for Charing Cross and Blackfriars – Waterseal was involved in the specification of the waterproofing membrane for both the new BDU and existing SSP structures. Due to possession and blockade working constraints, the specialist proposed the use of Wolfin IB to provide a waterproofing membrane to protect the structure. Throughout the pre-contract and installation process, Icopal / Wolfin offered extensive technical support including details bespoke to the project, copies of test reports and an overnight delivery service when required. Grant Weston, construction director at Waterseal (W & S), commented: “As a specialist supply and installation sub-contractor to the construction, civil and rail industries, we have built up our business to take on work across the whole of the UK. And we have responded to the challenges of Network Rail to become one of the prime sub-contractors tackling projects which have included Northern Hub, London Bridge, Airdrie Bathgate, Borders Line and Eden Brow in Cumbria. “Our involvement in the Bermondsey project was over a two year period, with our operatives continuously involved on site as programme dictated. The waterproofing was delivered during possessions and blockades throughout the duration of the project, with the membrane installation being overseen by Skanska and Network Rail.” Wolfin IB is an entirely homogenous thermoplastic waterproofing membrane that is resistant to bitumen, flux and mineral oils, as well as kerosene and acids. It is UV, microbe and red algae-resistant ensuring longevity while offering great flexibility with elongation at break of 300%. A proven track record extending back over 50 years of long term durability in different climatic zones, and lifelong weldability using solvent or hot air makes Wolfin IB a membrane that is always fit for purpose. The membranes are approved for roof and construction waterproofing, while accessories include preformed corner details to address upstands and other features. www.wolfin.co.uk Wolfin IB waterproofs Bermondsey Copper Stainless


RCI January 2018
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