The refurbishment of a roof in an exposed location, 35 metres high, can present its challenges. Stuart Hicks from Kemper System explains why a liquid waterproofing system was the best solution.
The correct product specification alongside a contractors’ skill and expertise were required during the repair of a 35-metre high barrelled roof area above an oil refinery at a food processing plant in Erith, London.
The barrelled roofs sections at the ADM Milling penthouse, adjacent to the River Thames in London, were experiencing water ingress and presented many key challenges for the contractors – its exposed location, the height of the building and access considerations for operatives, the busy and occupied nature of the food milling plant, and the requirement for a relatively quick and easy waterproofing solution.
The 100-year-old building consists of twenty-four food silos which are covered by three, 18m-wide barrel-vaulted concrete roof sections with interconnecting flat roof areas.
A quick yet durable waterproofing solution was required as the food milling plant was occupied and needed to remain fully functioning throughout the project. Any water ingress into the silos would result in the entire contents being disposed of, alongside a full decontamination and clean of the silo at considerable cost.
Working alongside contractors, Capital Roofing Co Ltd from Blackheath, London, the experienced team at Kemper System helped to devise a successful conservation programme to address water ingress caused by severe deterioration of the high roof area, and Kemper System’s Kemperol 2K-PUR solvent-free and odourless waterproofing membrane was specified for the project.
Chris Shulver, senior surveyor at Capital Roofing Co Ltd, said: “The height of the building and the width of the barrelled roofs meant scaffolding had to be erected at three levels onto the outer-barrel areas. We also had to install platform stages on the inner slopes of the roof to ensure our operatives could apply the waterproofing safely, whilst wearing harnesses. Restricted access presented challenges on this project, but we were able to overcome this thanks to the versatility and quick application of Kemper System’s Kemperol 2K-PUR.”
First, contractors removed the existing roof covering, a bitumen reinforced mesh system, to expose the rough concrete surface underneath.
This had to be mechanically removed and any repairs to the concrete carried out – a time consuming process which meant an easy-to-apply and quick curing waterproofing system capable of bonding directly to the exposed concrete was essential to ensure the project finished on time.
Once essential repairs had been carried out on the substrate, Kempertec EP primer was applied before the installation of Kemperol 2K-PUR liquid waterproofing using a roller, with a 165g reinforcement fleece laid directly into the wet resin.
More resin was then applied to ensure complete saturation of the fleece in a single, wet-on-wet process of application. The cured solution then forms a seamless, elastomeric waterproof membrane that cannot delaminate and is UV stable – directly addressing the issues of water leaking into the building.
This also included the refurbishment of several expansion joints on the concrete barrelled roofs using a specific detail comprising Kemperol 2K-PUR, and a joint backer rod made of polyethelene rope.
Because of the exposed location of the plant, next to London’s River Thames, operatives were faced with rapidly changeable weather and strong winds. Frequent wind meter checks were carried out to monitor the working conditions and to keep the site safe.
The handling and laying of sheet membrane materials in such conditions would not have been practical and could potentially have added an unnecessary level of health and safety risk for installers and employees of the plant. Kemper System’s two-component liquid applied system was therefore ideally suited to these conditions.
Due to the various chemicals used at the plant by ADM which created a risk of potential ignition, a cold-applied system was essential as the use of hot works was prohibited on site. Such was the high level of risk – even the use of mobile phones was forbidden.
Chris Shulver continued: “The ADM plant operates 24-hours a day, so works had to be carried out whilst the food processing mill was still occupied. A crane was used which allowed us to get the materials to the roof and remove any waste. This required precise planning and accuracy to prevent any disruptions to the working mill. Thanks to the versatile nature of Kemper System, installation was quick and we completed the project on time.”
Stuart Hicks at Kemper System added: “We have worked with Capital Roofing Co Ltd on many projects in the past, and our system was specified to refurbish an 85-metre high food silo at the same site in 2018.
“Kemper System waterproofing is eco-friendly as well as odourless, meaning work was carried out with little disruption to the plant. Working as a team with the contractor meant the end client was safe in the knowledge that Kemper System will provide a sound waterproofing system for many years to come.”
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