Green Roof Waterproofing
Green Roof Waterproofing
A greener approach to private/ social schemes...
Telford Homes' Parkside Quarter development on the outskirts of Canary Wharf delivers the ideal response to balancing the commercial realities of residential development alongside the need to create high quality, affordable homes for those who live and work in the capital but do not command the salaries that most private sector London homes require.
The 62 apartments in the development's main five-story block will be marketed to private buyers by Telford Homes, while a separate 4-storey block containing 17 apartments will be let by East End Homes and the housing association will also offer five apartments in a further four-storey block for shared ownership. While the target market for the private and social housing elements of the scheme may be very different, many elements of the specification are the same; including the green roofs that will feature on all three blocks.
Designed by David Wood Architects, the Parkside Quarter scheme is named after the acres of parkland that lies adjacent to it on the Isle of Dogs, in an enviable location that is only a few minutes' walk away from the banks of the Thames. The use of green roofs on all three apartment buildings, therefore, connects the residential scheme to its location, creating synergy with its green surroundings.
The green roofs were installed by roofing contractor Cawston Roofing using the cold liquid-applied waterproofing membrane, Kemperol V210, from Kemper System. This was used to waterproof the concrete deck and provide an ideal base for the inverted roof insulation and green roof elements of the project.
Explains Kevin Cawston from Cawston Roofing: "Kemperol V210 is the ideal base for a new build green roof because not only can it be applied quickly in a single process, saving time and labour, but it is also certified as root resistant so the planting used in the green roof will not compromise the integrity of the waterproofing."
Roof Build Up
Cawston Roofing began by applying Kemper System's EP primer to the substrate to seal the concrete and provide the ideal key for the liquid waterproofing membrane to bond to. Once cured, the installation team then applied the Kemperol V210 resin to the primed substrate, completing the roofs one section at a time.
Explains Stuart Hicks from Kemper System: "The Kemperol V210 resin saturates a polyester reinforcement fleece and cures to form a tough and durable, monolithic, seamless membrane with no laminations. It remains permanently flexible to cope with building movement and has a BBA certified service life in excess of 25 years."
Once the roofs had been waterproofed using the Kemperol V210 system, Cawston installed 240mm insulation directly on top followed by a 25ml deep attenuation layer; this enables rainwater to be stored to irrigate the green roof planting while allowing any excess water to drain off the roof. Finally, the growing medium was installed along with plug plants to create the finished green roofs.
Stuart Hicks adds: "Specification is extremely important when it comes to green roofs. Arguably the most important element is the waterproofing as the primary function of the roof is to protect the building. This must be robust enough to last as any leaks in the membrane can be difficult to access or repair once the green roof is established. Choosing a cold liquid applied waterproofing system, such as Kemperol V210, overcomes the common failures of many roofing systems as there are no seams, laps or joints that can be compromised. Client preferences and aesthetics have a role to play in the choice of green roof plants, but a key consideration should always be the location and prevailing climatic conditions as these govern the amount of light, heat, shade and moisture the roof will receive. At Parkside Quarter, the green roofs will create continuity across the private and social housing elements of the scheme as well as connecting it to its local environment."