Repairs to six blocks of flats were carried out by Ronacrete Approved Contractor Gunite (Eastern) Ltd for Lengard on behalf of Southwark Council. They used products from the Ronacrete RonaBond Concrete Repair & Coatings range as part of a larger refurbishment project costing around £4m.
Main contractor Lengard was awarded an internal and external refurbishment project by the London Borough of Southwark. The refurbishment was carried out on six blocks of five, six and seven storey residential flats at St Saviours Estate, London SE1. The project required repairs to the fabric of the buildings.
Ronacrete Approved Contractor Gunite (Eastern) Ltd was sub-contracted by Lengard to carry out concrete repair and protective coatings, mastic joint sealing and brickwork repair.
Gunite cut out and prepared areas of damaged concrete, primed the exposed reinforcement with Ronacrete Standard Primer and then re-primed the reinforcement when the concrete was primed, before applying RonaBond HB40 high build polymer modified mortar.
RonaBond HB40 is a pre-packed high build polymer modified concrete repair mortar. It is often used to repair concrete on vertical surfaces and soffits where ease of application is as important as strength. It is typically applied in layers up to 50mm thick on walls on walls and 30mm thick on soffits.
RonaBond HB40 is particularly suited to the repair of overhead concrete, such as the underside of concrete staircases, which can become damaged over time, especially when exposed to the elements as the staircases are on the St Saviour’s estate.
The repaired areas were then made ready for decorative and protective coatings by the application of RonaBond Easy Skim FC. This is a pre-packed polymer modified mortar which is applied as a skim coat in thicknesses up to 3mm, to provide a smooth, hard finish to damaged, blemished and repaired concrete. It is a levelling mortar that provides a smooth “harder than plaster” finish to walls.
The final stage involved the application of decorative and protective coatings to the repaired surfaces. Two products were used at this stage, RonaBond Crack Bridging Anti-Carbonation Coating WB and RonaBond Anti-Carbonation Coating WB.
RonaBond Crack Bridging Anti-Carbonation Coating WB is a high build elastomeric, waterproof and carbonation-resistant façade coating based on water borne acrylsiloxane. It protects façades against water ingress while allowing diffusion of normal levels of background moisture vapour. It provides excellent protection against corrosion of the steel reinforcement when applied to reinforced concrete. The siloxane component improves dirt shedding properties and protects against leaching of contamination through the coating.
RonaBond Anti-Carbonation Coating WB is a smooth, coloured, water borne acrylic anti-carbonation coating for use on vertical surfaces, soffits and at DPC level. It allows the passage of moisture vapour so it is particularly suited for application to substrates which may contain entrapped moisture. It can be applied to external walls and façades and protects against water, frost, and weathering it is also an effective barrier against the damaging effects of carbon dioxide gas. RonaBond Anti-Carbonation Coating WB is available in a wide range of colours, BS or RAL colours can be produced.
The RonaBond products used by Gunite provided a complete four stage concrete repair system at the St Saviour’s Estate project. Stage one, bonding agent (primer), stage two, polymer modified repair mortar (RonaBond HB40), stage three, levelling mortar (RonaBond Easy Skim FC) and stage four, protective and decorative coating (RonaBond Anti-carbonation Coating WB and RonaBond Crack Bridging Anti-carbonation Coating) greatly improving the integrity of the concrete and appearance of the flats on the St Saviour’s Estate, as well as providing protection from further corrosive damage for years to come.