It has taken more than six years in the planning process, but the five tower blocks that make up the Chalcots Estate in Swiss Cottage, north London are finally receiving a long awaited multi-million pound make-over. Playing a prominent role in the transformation is the revolutionary Pilkington Activ™ self-cleaning glass which has been specified for all of the replacement glazing.
Part of the programme, being carried out by specialist cladding contractor, Harley Curtain Wall Limited, involves the replacement of the existing windows with proprietary aluminium windows with thermally broken frames, which complement the exterior insulated aluminium over cladding system also planned. All units were supplied and processed by Pilkington Plyglass, one of Pilkington UK's dedicated processing and merchanting branches. The decision to use Pilkington Activ™ self-cleaning glass was made jointly between the two parties involved in the scheme, the London Borough of Camden and Partners for Improvement in Camden (PFIC), a joint venture between United House and the Bank of Scotland Corporate. Bob Heapy, Chief Executive of PFIC explains the decision. “The blocks are up to 22 storeys high which presented serious challenges when cleaning,” he comments. “In addition, the whole theme of the refurbishment was based upon sustainability, value for money and reduced maintenance costs and Pilkington Activ™ represented an economic advantage over conventional glass.”
Main contractor, Rydon Construction suggested the use of Pilkington Activ™ as a solution, with residents of the estate included in the decision making process with the Authority and PFIC which resulted in a position that that all parties were delighted to accept. PFIC were able to bring experience from the private to the public sector, enabling them to join with the London Borough of Camden to value engineer the project.
“Revisions, refinements and in depth value engineering were demanded following the Treasury’s decision not to provide additional funding to the scheme,” comments Pat O’Neill, Deputy Head of Capital Projects at Camden council. “Revisions were made by the council in partnership with PFIC to bring the scheme to a point where all parties were comfortable with the design and the affordability envelope. The use of Pilkington Activ™ self-cleaning glass fits all criteria and we are delighted that it has become an integral part of the final design decisions. The scheme now meets Government aspirations on PFI, residents’ wishes and the Decent Homes Standard.”
Cleaning windows on tower blocks is a huge undertaking, especially when the new statutory requirements of the Working at Height Directive are applied, with new guidelines concerning cleaning practice and equipment requirements. Pilkington Activ™ combines an advanced technological innovation with a passive solution to current legislative issues. Additionally, over time, the installation of self cleaning glass can save substantial amounts of money as the need for specialist window cleaners is reduced.
The key element of the glass is a microscopically thin, transparent coating of titanium oxide which, when applied during the manufacturing process, ensures that it is permanent and last for the lifetime of the glass. The external surface of Pilkington Activ™ is cleaned continuously by harnessing the two natural elements of ultra violet light and rain. The coating reacts with ultra violet light from normal daylight to break dirt down and its hydrophilic or ‘water loving’ properties cause rain water to flow down the glass in an even sheet to wash any remaining deposits away. Only organic soiling is directly destroyed by the coating, though non-organic matter is usually held to the glass by the organic dirt to be loosened and carried away when it rains.
The £150 million, 15 year PFI scheme includes £70 million initial capital works costs funded by PFIC and the local authority from Central Government and involves major internal and external works to all 605 tenanted and 105 leasehold flats. The London Borough of Camden initially applied to the Government PFI Pathfinder scheme in 1999, the only route that could fund the scheme whilst meeting residents’ wishes to keep the Borough as their landlord. It is expected that this PFI Pathfinder project no the Chalcots Estate will take 40 months to complete, with Rydon Property Maintenance and United House Maintenance taking on the responsibility for maintaining the buildings over the next 15 years.