Using a combination of products that
have been designed to complement
the Permavoid system – such as
Permatex, Permafoam and Permafilter
– has allowed the project to introduce
and maintain greenery and trees,
including rain gardens – whilst having
the ability to filter and treat the water
before it enters the vast geocellular
tanks beneath.
Polypipe Permavoid geocellular units
are manufactured and designed to be
durable enough to withstand heavy
loads, and so the design includes car
parking above, whilst permeable
paving is incorporated to capture
rainwater run-off at source, directing
it to the units below.
Permafoam absorbs the right amount
of stored water to passively irrigate
the vegetation from below, whilst
the Permafilter, with its hydrophilic
properties, intercepts contaminants
At Melina Road 2,345 Permavoid cells Thames Water approved the Polypipe
were installed to create four separate Permavoid system for its light-in-
storage tanks to sit beneath new rain weight construction, allowing for
gardens. The tanks are able to store a faster, more efficient installation
88m3 of rainwater captured at source whilst improving the visual
via permeable paving, whilst each environment, attracting important
of the tanks feature a top layer of biodiversity and providing an
Permafoam – a highly absorbent and intelligent multifunctional solution
water retentive material, providing to prevent the historical sewers from
31 litres of water storage to upwardly flooding.
and oil from the road surface above. irrigate the rain gardens above. During rainfall events, the Permavoid Each rain garden is also connected has given the residents peace of mind
to the local sewer network to allow during extreme weather events whilst
excess water to discharge back into providing a pleasant environment
the network at a lower flow rate, to enjoy – one that’s now rich in
sewer system. managing water at source. biodiversity.
The water, in part, is reused to help A total of 430 Permafoam cells were Polypipe has produced a detailed guide
installed to cover a combined area for sector specialists called Inspiring
of 108m2 and provide water supply Green Urbanisation which includes
for vegetation above. This technique projects similar to the Green Streets
mitigates flood risk during storm as well as ingenious drainage solutions
events, while sustaining plant growth for all kinds of landscaping and design
and providing additional green space projects.
tanks provide storage for large
volumes of surface water whilst
restricting the flow into the existing
maintain soil moistness within the
tree pits, feeding the trees and helping
to attract biodiversity, cool the air
and help to reduce CO2. Whilst the
Permafilter, with its hydrophilic
properties, intercepts contaminants
and oil from the road surface above.
in the local urban environment.
As a result, the Green Streets project
The guide shows how water
connects urbanisation and transport
infrastructure. It also demonstrates
just how these components work
together to achieve successful
water management solutions and
demonstrate multifunctional benefits.
Readers will be able to discover
innovative ways to introduce
environmental features such as urban
farming, biodiversity and climate
cooling to both new and refurbishment
projects of any scale.
To download a copy of the guide
go to www.polypipe.com/civils-
and-infrastructure