Ronacrete concrete repair on a grand scale
12 Jan 2011
Three nine-storey blocks of flats, at Loughborough Estate Lambeth, were repaired using Ronacrete specialist concrete repair products; started in 1993, it was the largest concrete repair project in Europe of its time.
The renovation work which affected 239 families included not only concrete repair but also roofing and window replacement.
The concrete repair work began with the removal of existing coatings to the concrete, using low pressure water jetting and grit blasting – the low pressure reduced the noise nuisance to residents and minimised the amount of concrete removed. Ronabond Fongimousse Plus was then applied to kill off mould, fungal growth and algae.
The damaged concrete previously identified by the surveyors was cut out to expose sound concrete and clean steel. Rust was removed from exposed steel by wire brushing – no need to spend time grit blasting to bright steel when using Ronacrete materials (saving time and therefore money, especially important on a large scale job). It was then primed with two coats of Ronafix and cement.
The Ronafix Mix Design D repair mortar of cement, sand, Ronafix and water was mixed and applied to replace the removed concrete. (Mix D is now available pre-packed as Ronafix Pre-packed Concrete Repair Mortar)
When repairs were complete a roller applied textured slurry coat of Ronafix, cement and sand was applied to the walls and soffits to mask the repairs and provide a regular surface to receive the Ronabond Joltec Smooth coating. A primer for the coating system was applied followed by an intermediate coat of Joltec Smooth, an elastomeric anti-carbonation coating, and a top coat of Joltec Granited was used to achieve surface texture and appearance. Ronabond Zolpacryl, a protective and decorative water based anti-carbonation coating for use on vertical surfaces, soffits and at DPC level was applied to soffits and at DPC level, to allow free passage of moisture vapour.
Ronabond Joltec was chosen for its; ability to bridge even large dynamic cracks, durability and waterproof properties, resistance to carbonation, tenacious bond to concrete and the breadth of its standard colour range. There are four systems within the range of each pigmented Joltec product, allowing bridging of crack widths ranging from fine hairline up to 2mm, beyond the capacity of most elastomeric coatings. The Joltec range also includes Ronabond Joltec Transparent, a clear elastomeric anti-carbonation coating for use when an original architectural feature must be retained and Ronabond Joltec Anti-Graffiti Coating,a clear coating for application to concrete or other Ronabond coatings.
To indicate the size of the project, 14,000 litres of Ronafix, 31,000 litres of Joltec and
Zolpacryl were used; 20,000 mof vertical surfaces and 10,000 mof soffits were treated. For large scale projects such as this one Ronafix can be supplied in 1000 litre IBCs.
One of the main reasons Ronacrete products were specified was that they were available with the assurance and comfort of a 10 year Insurance Backed Guarantee, something many local authorities have come to rely upon after suffering early failures.