Spring '21

has moved
away from
brick-based
aggregate
mixes towards
horticultural
solutions
whilst taking
into account
recommendations
and limits on organics
and other ingredients
as laid out in BS 8616 and
the GRO Code. The result is a deep
growing medium that offers optimum
levels of nutrients and aeration
supported by suitable drainage. The
substrate is environmentally friendly,
being free of peat – which also shrinks
over time, affecting plant performance.
It utilises coir – a waste product from
the coconut industry – green compost
and recycled lightweight aggregate.
Plant care and considerations
The all-important plants receive the
same level of thought and care, as Julian
explained: “Our plants are grown from
seed on our farm and comprise a range
of hardy native sedum to encourage biodiversity,
strong growth across the roof
and a variety of flowers, colours, leaf
structures and a haven for pollinators.
We recently launched a native perennial
wildflower option, allowing clients to
enjoy native flowers throughout the
seasons. All our pre-planted cassettes
are grown to maturity on the farm
so the plants are established when
delivered to site.”
Water management is key to the
success of any green roof. Modular
systems control this via the substrate
and design of the tray. Wallbarn’s
recycled polypropylene M-Tray cassette
has drainage holes strategically
placed – but not around edges – to
ensure beneficial water retention to
prevent plants dying back at edges.
To aid installation each tray has hand
grips and connectors to knit units
together tightly and securely. Corners
are rounded to avoid sharp edges. At
100mm deep, the trays
provide optimum space
Contact
Wallbarn
for healthy roots and therefore plants.
As with any green roof system, it is
important to consider time spent in
transit and the need to un-pack them
within 24 hours of delivery to ensure
optimum plant health. If left too long
on transport crates, enzymes begin
to break down the plants, so Wallbarn
advises an absolute maximum of 48
hours.
Conclusion
Modular systems aren’t suitable for
every project but they are suitable
for many and can make a green roof
feasible where a mat system isn’t an
option, particularly where roof access
is limited. They provide, quite literally,
green roofs that are box fresh for quick
installations and instant roofs.
Images: Below, a Wallbarn
installation in Wimbledon;
opposite page and top:
M Tray installed.
T: 020 8916 2222
www.wallbarn.com
Tweet: @wallbarn