weber.cem Products Repair Concrete Ferrier Tower

weber.cem concrete repair products are being used extensively in a major £7 million refurbishment project of the Ferrier Point tower block in the London Borough of Newham. This 66-metre tall block of apartments, built in 1968, rises 23 storeys to be the tallest block still remaining from the many built in London around that period.

The project is being seen as a flagship renovation by Newham to prove that today’s building technology can push up sustainability and performance to achieve Decent Homes standard for the 143 apartments. Approved plans show the building renovated throughout with extra insulation added prior to the existing concrete structure being covered with rain-screen cladding for a practical and modern look with the south face carrying 370m² of solar photovoltaic panels to generate sufficient energy to power the communal areas and lifts.

Main contractor Rydon is replacing kitchens, bathrooms and renewing electrical, heating and gas systems whilst structural changes will include triple glazed windows and the enclosure of the existing open balconies. Concrete Restorations Ltd is already at work on the renovation of the core structure and the precast panel facings where moisture ingress has rusted some steel reinforcing bars causing the surrounding concrete to “spall” leaving the rebar further exposed to the elements.

An abseil survey was carried out as part of the architects planning process which had started as far back as 2006. Approval for the project was given in early 2007 and work commenced in June that year and is due for scheduled completion by August 2010. With climbing platform masts secured to the building a thorough hammer survey was conducted to identify the actual extent of damaged concrete.

The effected areas have to be cut out to a depth that clears behind the rebar and along the bar to where the concrete is sound. The steel is cleaned as well as possible and then two coats of weber.cem keycoat are then applied by brush to seal the steel and the existing substrate surface to aide the bonding of the repair concrete. weber.cem keycoat contains migrating corrosion inhibitor to reduce the rate of corrosion in the vicinity of the repair and is formulated to BS EN 1504-3.

The concrete repair is made using weber.cem HB30, a high-build, polymer modified cementitious mortar that can be hand packed into the primed void. A wooden float is used to compact the repair material. Where deep cut outs are present layered applications must be made allowing the material to dry between application. Maximum single layer depth is 75mm. Where appropriate, shuttering is being used to form sharp edges on window aperture edges and panel joints.

The policy for Ferrier Point is to add protection now that will offer a further 30 years at least of the life of the building. Concrete Restorations team then spray-applies a coat of weber.tec guard MCI which is a corrosion inhibitor that migrates as it is absorbed by the concrete to preserve the embedded steel reinforcing bars. It forms a mono-molecular protective layer around the steel. The weber.tec guard MCI is applied at a rate of 0.25 litres/m².

The final process in the repair and preservation phase before the insulation and cladding is installed is to jet wash the entire concrete surfaces and apply two coats of weber.cote smooth which is an acrylic anti-carbonation coating that is resistant to chloride ion ingress but does allow vapour diffusion.

Further details about Weber concrete repair systems are available on 01525 722169, or visit www.netweber.co.uk for product information, performance criteria and case studies.