Faced with significant structural damage caused by chloride penetration and the subsequent corrosion of the steel reinforcement, The London Borough of Hamlets needed a proven means of repairing the damage and protecting the steel reinforcement of two of its twelve storey residential buildings. Following a careful assessment of the properties, consulting engineers Global Engineering Design Associates specified a range of concrete repair products from Sika.
Designed by renowned architect Berthold Lubetkin, George Loveless House and the neighbouring James Hammett House were two of the first to feature high level blocks using reinforced concrete. But over the years, the two blocks had fallen into disrepair and the external coatings, walkways, columns, decks, aggregate panels and mastic joints were in need of a serious refurbishment.
“George Loveless House and James Hammett House were built in 1957 and due to lack of investment over recent times, the appearance of the building had been affected,” commented Jamie Carswell, Director of Investment of Tower Hamlets Homes. “When Tower Hamlets Homes was set up in 2008 to manage the Tower Hamlets Council housing stock, both buildings were included on a programme of capital works. The concrete works helped to achieve a sympathetic restoration of the block and residents have been positive about the works. A range of products from Sika were selected.”
Following an assessment of the properties, consulting engineers, Engineering Design Associates, created a specification that was designed to repair and protect the building through the use of high performance mortars, corrosion management systems and sealants produced by Sika.
Sika’s Armocrete, a cementitous free flowing micro-concrete repair system, was used to repair large sections of the building columns while all the exposed concrete and brick surfaces on the building were protected by SikaGard 702W, a silicone coating which is water repellant and ensures the aesthetic appeal of these tower blocks. On soffits and parapet walls, the flexible anti-carbonation coating SikaGard 675W was used as a protective coating and offers proven protection against weathering and ageing.
Smaller repairs to soffits, columns, decks and aggregate panels were completed using the Sika Monotop Concrete Repair system. A cementitious one part system which comprises polymer modified mortars, the system has an excellent resistance to water and chloride penetration, helping to prevent future damage to the concrete structure.
Another vital requirement was the sealing of all joint repairs on the blocks to create a water and air tight building envelope. With incorrect specification of sealants often resulting in failure in the form of water ingress, air leakage, staining of building materials plus the associated cost with putting this right, Sika was able to advise on the best solution. This saw the use of Sikaflex AT Connection, a one part moisture curing elastic sealant based on Hybrid Polyurethane technology.
To complete the repairs, the balcony desks, which were badly cracked and letting water through, were attended to. To tackle the repair, the Sikafloor Pronto fully fleeced system was used. Comprised of a low viscosity primer, a self-smoothing screed and a flexible acrylic seal coat, the system offers excellent mechanical, chemical resistant and weathering properties. Featuring PMMA (polymethyl methacrylic) the extremely fast curing non-slip resin flooring system is ready for foot traffic after one hour and fully cured after two, helping to minimise any disruption to the blocks residents.
With each of the Sika products offering a proven track record exceeding the requirements of BS EN1504, the regulations for concrete repair and protection, and an easy installation process once on site, the concrete repair system specified offered Tower Hamlets Homes a cost effective and reliable way to repair the damaged areas and extend the life of its properties. The families that live in the two blocks now benefit from its attractive new appearance and additional peace of mind that the structure is protected from the onset of any further degradation for years to come.
For further information on Sika’s range of concrete repair products, visit www.sikaconstruction.co.uk