A greener approach to private/social schemes

London’s residential property market is notoriously complex, with prices for private sector new builds far outstripping most other UK locations. However, the need to ensure that ‘ordinary’ Londoners can continue to live and work in the city and the sprawl of the capital’s major institutions outside of the square mile into East London has caused a democratisation of the housing needs in some locations: amongst them E14 – the postcode for Canary Wharf.

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.

Green Surroundings

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 fact that the green roofs have been specified for both the private sector and social housing elements of the scheme demonstrates that they are no longer the preserve of a certain demographic of people, or a certain type of building, and are now available to all in what was once a working class postcode. It also illustrates how far green roofs have come in terms of entering mainstream specification: ‘eco’ schemes are now being used to create a more harmonious built environment, with low maintenance planting and a robust, durable roof build up to maximise service life and encourage local bird and insect life.

The green roofs were installed by roofing contractor Cawston Roofing using Kemperol V210, a cold liquid-applied waterproofing membrane, from Kemper System.

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 the polyester reinforcement fleece and cures to form a tough and durable, 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 depth of insulation directly on top of the waterproofed substrate to enhance the buildings’ thermal performance in line with building regulation requirements. The team then installed a 25ml deep attenuation layer, which 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.

Specification Expertise

Stuart Hicks continues:

“Ensuring the correct 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.

“The waterproofing system used must be robust enough to last because any leaks in the membrane can be difficult to access or repair once the green roof is established. It must also offer proven root resistance to ensure that the waterproof protection cannot be damaged by planting. 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.”

Careful selection of planting for green roofs is also critical and must factor in client preferences, aesthetics and local eco systems. However, the location and prevailing climatic conditions, which govern the amount of light, heat, shade and moisture the roof will receive, also need to be a major part of the planting specification process.

Stuart adds:

“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 with a long-lasting, low maintenance and aesthetically pleasing solution.”