Winter 2022

GREENSCAPE
Ensuring Best Practice for Green Roof & Solar PV Projects MAGAZINE
WINTER 2022
Spreading the Word
Maintenance Tips
Fire Mythbusters
Performance
Academic Corner: Irrigation
News, Views & Projects
Plant Selection
In collaboration with the Green Roof Organisation

Part of the Langley Group
Bringing living
roofs back to life
Is your living roof getting the care it needs?
Welcome to Eco Green Roofs, the experts in designing, installing and maintaining
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Following our detailed survey to assess your needs,
we’ll recommend a bespoke maintenance programme
to protect and extend the life of your roof.
Opening up the green envelope.
Part of the Langley group, we are one of the UK leaders in
green roof technology and green infrastructure, providing
design, installation and maintenance services for:
Eco roofs Living walls Biodiverse roofs Blue roofs
Scan the QR code below to speak
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Solar and
biosolar roofs
Podium and
Landscaping
Planting schemes
globe
envelope
phone
www.e-egr.co.uk/maintenance
maintenance@egr.co.uk
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Part of the Langley Group

GREENSCAPE
IN THIS ISSUE...
Matt Downs
Editorial Director
mattdowns@media-now.co.uk
07963 330774
www.greenscapemag.co.uk
As we approach the end of another challenging year for construction, one
positive from 2022 is the increased focus on sustainability and the environment
from manufacturers of construction materials, the government, and end-users.
Don’t get me wrong, there’s a long way to go for construction and the built environment
in this area, but across all the construction titles we publish at Media Now, there’s a clear
sense that many manufacturers are taking this more seriously and looking at their
internal processes and the products they produce, as they look to meet the demand of
their customers and end-users who are increasingly looking for ‘green’ solutions.
Readers of this magazine and contributors are already well aware of the many positive
impacts green roofs and associated systems can have on the built environment, but
it’s clear the goal is to reaffirm this message and take it further afield. With this in
mind, Maggie Fennell of GRO and Boningale Group has been doing exactly that in
recent months, and on page 10 she discusses some events where she’s been raising the
profile of GRO and green roofs to other stakeholders in the supply chain. Discussing the
importance of networking and creating new relationships, Maggie explains: “We need
to learn from each other’s experience, otherwise the industry will not develop as fast or
as effectively as our planet needs it to.”
But as we know, it’s not just about promoting green roof systems; knowledge around
correct installation and maintenance is vital to maximise the many environmental
benefits. As such, this issue features articles on the key steps for maintaining your
green roof from the experts at Eco Green Roofs (page 20); the team at GRO dispel the
myth that deeper substrates mean more expense (page 22); plus we talk substrate
composition with Wallbarn and Sedum Growers (page 24). Enjoy the issue!
Front cover image courtesy of Wallbarn. Wallbarn discuss
substrate selection on page 24, and find out more about the
company at www.wallbarn.com
GREENSCAPE
www.greenscapemag.co.uk
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Supported by:
CONTRIBUTORS TO THIS ISSUE...
This magazine and its packaging can
be recycled.
p 10
Spreading the
Word
Maggie Fennell,
Marketing Chair
at GRO.
p 14
Academic Corner
Dr Tom
Young of The
Environmental
Partnership.
p 28
Solar powers on in
2022
Stuart Nicholson,
Roof Systems
Director Marley.
Maggie reports back from recent
exhibitions which have seen the GRO
team networking and interacting with
the supply chain to raise the profile of
green roofs and associated systems for
projects.
P 10
In part two of his focus on drought
tolerance of green roofs in a changing
climate, Dr Tom focuses on the
importance of irrigation and getting it
right first time, plus looks at the different
techniques.
P 14
Stuart looks back on what has been a big
year for the solar PV sector, in no small
part thanks to the introduction of the
amendments to Part L, and explains why
he believes the specification of PV on
roofscapes will only increase.
P 28
www.greenscapemag.co.uk • GREENSCAPE WINTER 2022 3

Contents
NEWS
06 Well read: Find out more about
GRO’s collaboration on Journey to
the Green Roof, a new book aimed
at educating children about green
roofs
08 Social gains: Sika has donated a
green roof and other materials to
a Salford project which is creating
a safe, indoor space to host events
and activities to tackle social
isolation in the area
GREEN ROOFS
18 Growing resilience: Dr Elisa Olivares
Esquivel discusses plant plasticity and
variation for climate-smart green roofs
20 Maximising performance: The
experts at Eco Green Roofs (EGR)
outline the key maintenance steps that
will help ensure the performance and
longevity of your green roof
24 What lies beneath?: We talk
substrate composition and
standards with Wallbarn and partner
company Sedum Growers
4 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

GREENSCAPE
SOLAR PV
28 The year when Part L became
real!: Marley’s Stuart Nicholson
looks back on a crucial year for the
solar PV sector, and outlines why
he feels this is just the beginning
for the specification of solar PV on
roofscapes...
REGULARS
10 Spreading the word: Maggie
Fennell of GRO and the Boningale
Group reports back from recent
exhibitions where she’s been helping
raise the profile of green roofs and
GRO
14 Academic Corner: In the second
part of his focus on drought
tolerance of green roofs in a
changing climate, Dr Tom Young
focuses on irrigation techniques and
the importance of getting it right
22 Mythbusters: Our latest column
dispels the myth that deeper
substrates mean more expense
www.greenscapemag.co.uk • GREENSCAPE WINTER 2022 5

News
GREENSCAPE
GRO COLLABORATES ON NEW BOOK TO HELP INTRODUCE
TOMORROW’S CONSUMERS TO GREEN ROOFING
LIVING WALL AWARD
Biotecture is celebrating winning a
BALI National Landscape Award for
the Canary Wharf estate Greening
Phase One.
The extensive urban greening
project was selected as a winner in
the Exterior Living Wall Category
in what the judges said was a
‘phenomenally’ high standard of
entries in this year’s award.
Biotecture delivered PlantBox living
walls in prominent locations across
the Canary Wharf estate in 2021.
They are now helping to enrich
the public realm and contribute
to Canary Wharf Group’s (CWG)
ambitious sustainability goals.
The judges commended Biotecture for:
“A green initiative worthy of support.
A committed contractor coupled with
a client willing to experiment.” They
go on to say: “The modular living wall
system has some science behind it and
fulfils the client’s brief”.
In a nod to the science, the BALI
judging panel recognised how the
Biotecture living walls are helping
to improve air quality, attenuate
rainwater and increase biodiversity
for residents, commuters, workers
and visitors to the area.
Richard Sabin, MD at Biotecture, said;
“Winning a National Landscape Award
is hugely significant because it helps
us highlight the benefits of adding
greenery and biodiversity into the
urban realm. These benefits are hugely
significant to people living and working
in the Canary Wharf area, although it is
the aesthetic appeal of the living walls
that people notice first!”
www.biotecture.uk.com
Angela Lambert, on behalf of GRO,
discusses Journey to the Green Roof,
a book for youngsters from GRO and
Tales from Mother Earth, written by
Jenny Bailey…
“The UK Government’s Build Back
Greener Strategy sets out policies and
proposals for meeting the country’s
target of being net zero in 2050.
I’m in my mid 50’s and there’s no
guarantee I’ll be around to celebrate
the achievement. However, by then
my grandchildren will be in their 30’s
and 40’s and will likely be in a position
to not only benefit from the initiatives
but possibly to influence decisions
about the built environment.
“That’s why, when the GRO Marketing
Team told me about their collaboration
with Tales from Mother Earth to publish
a children’s book which highlights the
benefits of green roofing, I was instantly
keen to learn more. The new book
is titled Journey to the Green Roof
and highlights the benefits of green
roofing from the perspective of two
very characterful beneficial insects. I
won’t give any more away, but I have
seen the first draft and I can confirm
that the story is very compelling, highly
empathetic and absolutely delightful.
The characterisation puts me in the
mind of Beatrix Potter – and we know
how evergreen her stories are.
“Author Jenny Bailey has successfully
published three other children’s
audio story books in the same style
as Journey to the Green Roof.
Phoebe the Bee follows the plight
of a honeybee and helps children to
understand how crucial biodiversity
is to the survival of our planet.
Spike the Hedgehog is an enigmatic
little character who illustrates the
challenges for wildlife in gardens and
Stanley the Water Vole highlights the
consequences of allowing plastic to
pollute our environment.
“Each book includes an audio
recording, so that children can follow
the printed words to help develop
their reading skills. There are also
puzzles and activities within the book
to engage little ones further. And in
Journey to the Green Roof, Dusty
Gedge has contributed a series of ‘fun
facts’ to help educate children (and
adults!) on the practical benefits and
the charms of living roofs.
“I urge you to visit Jenny’s website
to learn more about her books – and
perhaps purchase one or two for the
young people in your own life.
(www.talesfrommotherearth.co.uk)
“Journey to the Green Roof is on
track to be launched on World Green
Roof Day, 6th June 2023, and the
author, along with GRO, is offering a
unique opportunity for GRO members
to get involved. The hope is that
through members’ sponsorship, GRO
will be able to offer the book as a free
giveaway to schools and community
groups. Participating members
will have their logo printed on the
sponsors page in the book and can
nominate a school or group in their
area to receive copies.
“I’m only a humble copywriter with
a keen interest in green roofing,
but I can picture myself now, sitting
with a group of children in my
granddaughter’s primary school,
reading the story out loud and
showing the children some of the
plants that are mentioned in the
book. I’d tell them about the green
roofs to look for in our area, and I’d
like to think that the youngsters will
each take a copy of the book home
to read with family members. I’ll be
sponsoring some books - will you?”
Contact Chris Bridgman or Maggie
Fennell from the GRO to find out how
to sponsor Journey to the Green Roof.
www.greenrooforganisation.org
6 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

Proud to be
a member of
the GRO Code
The sky’s the limit
With a Green Roof System from Green-tech
1
2
3
4
5
1. Choice of soft and hard landscaping
materials available, including:
• Sedum Matting
• gtSedum Cassettes
• John Chambers Wildflower Matting
• John Chambers Green Roof
Wildflower Mix
• Turf
• Planters
2. Intensive or Extensive Green-tree
Roof Garden Substrate
3. Drainage Board System, including:
• Filter Membrane
• Drainage Layer
• Rootbarrier
4. Waterproofing Layer
5. Roof Structure
This diagram of a typical green roof construction is for illustrative purposes only to demonstrate the range
and types of products available for a green roof installation.
Green-tech is a leading supplier
of landscaping and green roof
materials. Our products have been
used in many high profile and
award-winning green roof projects
throughout the UK.
We can provide everything you
need for a successful installation,
including technical advice, project
specifications, CAD drawings and
of course, a full range of Green
Roof products.
For more information, book a
free Green Roof System CPD
presentation, to be delivered
online or in your office.
T: 01423 332100
www.green-tech.co.uk
sales@green-tech.co.uk
@greentechltd
@greentechuk
green-tech-ltd

News
PV INSTALLS UP IN 2022
Data from MCS (Microgeneration
Certification Scheme) for solar panels
installed on UK homes shows that
new solar PV installations surpassed
the total for 2021 just eight months
into 2022.
MCS, which defines and maintains
standards for small-scale domestic
renewable energy and heating across
the UK, has recorded all certified
installations on its central database
since 2008.
Figures show that 79,560 solar PV
installations were completed from
January – August 2022, a 30% increase
on the 61,431 installed in the whole of
2021. There was a 144% increase of
solar PV installations registered with
MCS in August 2022 – 12,411, compared
with 5,082 in August 2021.
The data combats concerns in
the renewable energy sector that
domestic solar PV demand would
diminish after the Feed-in Tariff (FiT)
incentive ended in April 2019.
In all, solar PV installations comprise
more than 80% of the 1.4 million
renewable installations so far registered
with MCS. This takes the total number
of ‘sunny roofed’ residential properties
to more than one million.
In 2021, small-scale solar PV
installations produced a peak of
3GW of electricity for the UK grid for
the first time ever, around the same
amount of power as the Sizewell C
nuclear power plant (3.2GW).
Ian Rippin, CEO of MCS, explained:
“With UK homeowners quite rightly
worried about the cost of living amid
rising energy costs, we are pleased to
report the installation of solar PV is
powering on as homeowners look to
invest in home-grown energy. We are
seeing more installations registered
on the MCS database and our certified
contractor base also continues to grow.”
www.mcscertified.com
SIKA DONATES GREEN ROOF TO
IMPORTANT LOCAL PROJECT
Leading roofing manufacturer, Sika,
has donated over £7,000 worth
of materials to a social enterprise
in Salford which is creating a safe,
indoor space to host events and
activities aimed at tackling
social isolation.
Created from two disused
shipping containers, the new
building is located at the Cleavley
Community Forest Garden in Winton,
which is run by Incredible Education
CIC, a social enterprise providing
nature-based services for local
communities through horticulture and
forest school activities.
Having access to the new covered
space will enable the garden to
host music events, health activities,
parent and toddler groups and
workshops all-year round; all with
the aim of improving community
connection.
The building will primarily provide a
secure indoor workshop to Salford
community group, Working in Wood,
which runs woodwork projects for
anyone over the age of 18 looking to
gain skills or meet new people. The
group, which helps to tackle social
isolation, has also been involved with
the construction of the new building,
having erected the timber frame
surrounding the containers.
The two shipping containers were
combined to form a 20ft x 30ft
room topped with a Sika Green Roof,
which blends in with the natural
surroundings and nods to the land’s
former use as a plant nursery.
The system build-up included SikaBit
VB-724 Air and Vapour Control
Layer (AVCL) VCL, 100mm Foil-faced
AL Sikatherm insulation and the
new, sustainable roof membrane
Sarnafil Advanced Technology
(AT) - the UK’s only Cradle to Cradle
Silver certified single ply
membrane. The membrane is
not only independently certified
in sustainability performance but
as it contains no plasticisers, oils,
chlorine or heavy metals it is ideal
for sustainable construction. Topping
this, the aluminium edge trim,
SikaRoof drainage layer, SikaRoof
Biodiverse substrate and a SikaRoof
Wildflower Blanket, created a natural
habitat for flora, fauna and wildlife.
The wildflower blanket was laid in
such a way to encourage the roof to
self-germinate with local seeds blown
by the wind onto the roof.
The install took four days and
was carried out by Sika-approved
installer, Chorley-based roofing
contractor, Enviroply Roofing Ltd,
who donated their time to the project
free of charge, alongside members
of the Sika roofing team.
Ian Bocock, Director and Education
Manager at Incredible Education
CIC, commented: “We’re all about
promoting mental health and
wellbeing in a green space so to be
able to host activities year-round
which build skills and confidence
is huge. Having the roofing
materials and labour donated to
the project was massive because
our budget was used up on
groundworks, steelworks, cladding
and in purchasing the containers.
To receive those donations was
fantastic and we’re thrilled with our
new green roof, which fits so well
within the garden.”
www.sika.co.uk/roofing
8 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

GREENSCAPE
Above: Alice, Georgia, Emily and Mark from
Green-tech Specifier
NEW WEBSITE LAUNCHED BY
GREEN-TECH SPECIFIER
Green-tech Specifier has launched its
new and improved website
www.gtspecifier.co.uk
Green-tech Specifier is the
specification team of leading
landscape supplier Green-tech. The
team was established to meet the
growing demand of Landscape
Architects, Garden Designers and
Contractors who required assistance
at the specification, estimating and
drawing stages of their projects.
The new and improved Green-tech
Specifier website addresses the needs
of Landscape Architects, Contractors,
and Garden Designers and showcases
the latest solutions and products for
urban regeneration and landscaping
projects, including a number of
solutions to address climate control,
flooding and biodiversity challenges.
Visitors will find a host of resources
to help support landscape design
projects, including:
• Resource library;
• Product calculators;
• Event calendar;
• Project assistance;
• CPD seminars;
• Past webinars;
• News articles & videos
Green-tech Specifier is a team of seven
that has the product knowledge and
technical expertise to provide advice,
guidance, and recommendations for
bringing landscape designs to fruition.
www.gtspecifier.co.uk
MCS PROVIDES ACCESS TO REAL-
TIME RENEWABLES DATA WITH NEW
DATA DASHBOARD ONLINE TOOL
MCS (Microgeneration Certification
Scheme), the standards organisation for
small-scale domestic renewable energy
and heating across the UK, has announced
the launch of its brand-new, interactive
online Data Dashboard to provide a
detailed analysis of the volume of domestic
renewable energy installations in the UK.
The MCS Installations Database (MID)
holds the details of every MCS certified,
small-scale renewable energy installation
in the UK since 2008, making it the most
comprehensive reference for small scale,
renewable energy installations in the UK.
The organisation says the abundance
of information in the MID puts MCS in a
unique position to share data-driven insights
to help manage the net zero transition.
MCS says Industry, Ofgem and BEIS (the
Department for Business, Energy and
Industrial Strategy) have long used the
MID as a single reference point to help
inform policy development, but this data
will now be made publicly available for the
first time. MCS says the new MCS Data
Dashboard will provide near-real-time
updates on MID data, tracking the adoption
of small-scale renewable installations across
the UK. Given the UK’s legally binding netzero
targets, MCS says the platform will
monitor the current uptake of small-scale
renewables, highlight current and past
trends, and identify opportunities for further
development and growth. The organisation
points out already this year, it has recorded
continued growth in solar PV installations,
with the number of installations recorded in
the first eight months of this year exceeding
the total number of installations in 2021
(see page 8).
By creating dynamic visualisations, MCS
says users of the Data Dashboard will be
able to view the uptake and distribution
of small-scale renewable installations
across the UK in near-real-time. MCS
points out data is updated every 24 hours,
instantaneously providing the most
accurate picture of home-grown energy
available across the industry. The platform
is also said to provide insights into the MCS
certified contractor community, identifying
growth and opportunities in green jobs
as the volume of low carbon installations
continues t to increase.
The MCS Dashboard is said to be divided
into two sections: Installation Insights
and Scheme Insights; the Installation
Insights section showcases the uptake and
geographical distribution of renewables,
where they’re used successfully and
where opportunities for growth are, whilst
Scheme Insights enables users to compare
the growth of different technology types
and shines a light on the contractor base
installing them. MCS says both can be
filtered by year, location, technology and
installation type, with image and data
exports available to download.
Ian Rippin, CEO of MCS, said: “Robust data is
the essence of strong decision-making. Our
Data Dashboard has been a long time in the
making and our efforts have paid off as we
roll out our invaluable data via a real-time
platform that will be a useful tool for several
audiences. We believe this data will be
important to people working on renewable
installations and those who influence the
policies for our low carbon future.
“This is why we believe it is important
to make our data freely available and
we encourage anyone in the domestic
renewable energy sector or working on
energy system modelling to use it to their
advantage. The MCS Data Dashboard will
continue to evolve, and as we look to build
its capabilities out even further we seek
honest and constructive feedback from
users.”
mcscertified.com/about-the-mcs-datadashboard/
www.greenscapemag.co.uk • GREENSCAPE WINTER 2022 9

EXHIBITIONS & NETWORKING
RAISING AWARENESS & BUILDING
BUSINESSES THROUGH NETWORKING
Maggie Fennell, Marketing Chair for GRO and board member
representing Boningale Group, reports back from recent
exhibitions which have seen GRO interacting with the supply
chain and raising the profile of green roofs through interaction
with key stakeholders...
GRO members are making
the most of trade shows and
exhibitions in order to meet with
and create relationships with industry
experts, manufacturers, growers,
specifiers, planners and potential
clients.
Maggie Fennell, Marketing Chair for
GRO and board member representing
Boningale Group, recently represented
GRO at the Landscape Show, in
Birmingham, where she says she was
kept on her toes by a constant stream
of visitors wanting to learn about green
roofing. The audience consisted largely
of garden designers and landscapers
who wanted a greater understanding of
domestic green roofing.
Building on the success of the
Landscape Show, GRO says it is
planning to visit Futurebuild at London
ExCeL in March 2023. A very different
audience, but with a similar objective
– to create links within the industry
so that expertise can be shared and
opportunities created.
Here’s Maggie’s report from the
Landscape Show and her thoughts on
Networking:
“In an industry which relies on the
successful cooperation of many
disciplines, networking is key to growing
the marketplace and offering a wide
variety of green roofing solutions.
Although the word ‘networking’
conjures up the worst kind of images
of ‘beige’ buffets and small talk, I am
Above: Maggie Fennell presenting on behalf of GRO at a recent industry trade show.
happy to report that this has not been
our experience at all.
“One of the core benefits the Green
Roof Organisation offers to members is
that kind of networking that builds trust
and confidence. We need to learn from
each other’s experience, otherwise the
industry will not develop as fast or as
effectively as our planet needs it to.
“The Landscape Show in September
provided a great opportunity to connect
with domestic green roof installers and
designers and – just as importantly –
with many prospective and fledgling
green roofers who are at the very
beginning of their journey towards
including living roofs into landscaping
projects.
“In a targeted trade show like
Continued on page 12 >>>
10 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

EXHIBITIONS & NETWORKING
See GRO at
Futurebuild
7-9th March 2023,
ExCeL London
Book tickets at:
www.futurebuild.co.uk
GRO has enjoyed success at recent exhibitions, creating good relationships and educating the supply chain on the benefits of green roofs
>>> Continued from page 10
Landscape, there are rarely huge
volumes of traffic, which means more
time to spend with individuals. In that
way, each conversation is more detailed,
more specific and more personal. GRO’s
objective for this event was to reassure
new entrants to the industry that they
will be welcomed and supported at
every step of the way. I came away from
the two-day event feeling confident that
we had achieved just that.
“NEC Birmingham provided an ideal
venue for this show. Its central location
is easily accessible and we saw visitors
from all over the UK. The show
organisers did a fantastic job of turning
the cavernous, industrial hall into a light,
bright meeting space with four seminar
theatres, several demonstration areas
and a central cafe area with superb
flapjacks! The presence of plants on
every other stand certainly helped
create a good ambience too.
“On day one of the show I teamed up
with Kay Davies from Oxford Green
Roofs to give a presentation entitled
‘How To Get Going In Green Roofing’.
The attendees responded well to our
mix of technical background, varied
case studies and signposting towards
resources that will help businesses take
the next step towards green roof design
and installation.
“Kay has been helping to advise GRO
on further support needed by domestic
green roofers. As a starting point, our
organisation has set up a Facebook
Group to encourage communication,
support and cross referrals. Join
‘GreenRoofOrganisation GRO Official’
on Facebook to share your thoughts,
ask questions and tell us more about
your work in the green roof industry.”
Looking ahead
“Looking ahead to next year, GRO has
been in talks with Futurebuild about
providing our members with the
opportunity to engage face to face
with policy makers, planners, landscape
architects and architects. Plans are
very much in their infancy but we
hope to provide GRO Members with
opportunities to come together with
stands and interactive demonstration
spaces that provide a great educational
experience for visitors.
“Green roofs lend themselves to visual,
practical, and tactile displays which can
include different plant types, colours
and textures. These conversation
starters are a great lead-in to explain
the benefits of green roofs and how
following the GRO Code of Best Practice
will optimise their performance.
“If you’d like to be involved, please get
in touch with one of the GRO board
members.”
Sign up for GRO updates to keep in
touch with the organisation’s news,
views and activities.
Simply email: membership@
greenrooforganisation.org and the
team will do the rest.
12 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

SAVVY SHOPPER
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Laura Crombie
Brand Director
Real Homes
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ACADEMIC CORNER
DROUGHT TOLERANCE FOR A CHANGING
CLIMATE – PART 2
By Dr Tom Young, Blue-Green Infrastructure Associate at TEP.
When I spoke about water
on green roofs in my last
article, I mentioned in passing
the role of irrigation on green roofs.
However, it really deserves a full article
to itself. Irrigation can be a contentious
issue on green roofs, but very often
it is not thought through properly.
In many situations irrigation may
not be appropriate for a green roof.
However, due to our changing climate
some form of irrigation, either as a
backup or an establishment method,
is recommended in some situations.
As a caveat, this article is designed to
speak to a UK design audience.
Other countries have much
more extreme climates than
us and therefore irrigation
requirements are very
different.
When and how to irrigate
You need to be very careful
when deciding to specify an
irrigation system on a green
roof. An irrigation system shouldn’t
be used to make up for a poor or
inadequate design. It should be used as
a backup system to cope with extreme
events. With extreme events becoming
more common, the need for additional
irrigation is likely to increase in the
future. However, green roof design
should also adapt to changing climate
i.e. different plant species, landscape
design or substrate depth.
There should be a hierarchy of water
sources used for any irrigation system.
Potable mains water should always be
used as a last resort as there are plenty
of more sustainable – and cheaper in
the long term – sources of water. This
list provides a rough water source
hierarchy that should be followed:
Left: Dr Tom Young. Above: Figure 1 – Illustration shows a potential fog net and
solar panel dew harvesting green roof. See Fog water section on next page.
1. Rainwater direct or
reuse (this could also
include fog/dew water)
2. Recycled greywater or
air-conditioning condensate
3. Treated wastewater (hopefully to be
made more available in the UK in the
future)
4. Saline water (very much location
dependent)
5. Potable water.
Rainwater harvesting
The most obvious way of irrigating a
green roof is to collect all the water
that falls on it. A degree of water is
retained anyway but green roofs will
drain like a normal roof when at field
capacity. A variety of methods exist to
capture drainage water. These range
from large tanks at ground level, to
more innovative blue-green roofs which
store water on the roof (see subsurface
irrigation section). Water can then be
moved from these storage areas with
either pumps, or passively wicked into
the substrate on demand.
Air conditioning condensate
Air conditioning (AC) units produce
condensate water as part of their
mechanical process. In UK cities
the use of air conditioning units is
becoming much more prevalent. An
AC unit designed for a single room or
apartment on a green roof in Beirut
provided between 0.2-1.2 l hour -1
depending on the humidity
(Sisco et al. 2017).
This wouldn’t be enough to support a
large green roof but could be used to
help supplement other water sources.
The advantage of this water source
is that as temperatures increase and
water demand rises, the amount of AC
water available is also likely to increase.
14 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

Greywater
Greywater can be defined as
wastewater from domestic and
industrial uses. The easiest and safer
to use sources of greywater include
kitchen drains, hand washing from sinks
and domestic clothes washing. This can
be reused on green roofs with minimal
treatment, with the green roof actually
providing the treatment in some cases.
Due to its regular production, large
amounts of storage are not needed as it
is a very predictable supply
(Mahmoudi et al. 2021).
Fog water
In coastal or humid environments, a
surprising amount of water can be
collected from fog/dew. Fog collectors
can range from giant vertical mesh
nets which capture fog, to adapted
solar panels which collect dew. A study
of different warm climates found that
between 1.2-15.6 l m -2 day -1 could be
harvested from fog water and 0.2-
0.7 l m -2 day -1 from dew. This could
potentially supply 100% of the irrigation
need of green roofs in these climates
(Pirouz et al. 2021). Figure 1 (left)
shows a potential fog net and solar
panel dew harvesting green roof by
Pirouz et al. 2021.
Saline water
Saline water is another option to
use on green roofs. Saline water can
come directly from the sea, or even
from brackish groundwater or treated
wastewater. In an extreme example,
Ntoulas & Varsamos 2021 irrigated
warm season turfgrass in a green roof
setting with seawater from Athens’s
harbour. The idea was to see if the
turfgrass could be kept alive under
extreme conditions i.e. during a long
summer drought when no other
water was available. They showed that
although turf quality declined during
the irrigation period, turf still survived.
An effective method was to over
irrigate with salty water in order to
Above: Figure 2 shows an inappropriate irrigation system on a green roof in the UK.
prevent salt build-up in the substrate.
The extra water, despite being salty
helped to keep salt in solution and
pass out of the substrate as the excess
drained (Ntoulas & Varsamos 2021).
Benefits of irrigation
It sounds obvious, but in the harsh
green roof environment a small
amount of extra water, specifically
during extended dry spells, can
significantly increase plant survival.
This is particularly true in the first few
establishment years of a green roof. It
also applies to green roofs that have a
wider range of plants other than very
hardy succulents. Irrigation provides
a greater amount of plant available
water which prevents plant death,
lowers substrate temperature, and
reduces stress on plants. A study in the
US showed that irrigating green roof
modules could reduce their average
summer substrate temperature by
between 2-4ºC, as well as reducing the
level of extreme substrate temperatures
(Guckenberger et al. 2011). This can
also then result in greater ecosystem
service benefits, for example a
greater cooling effect on the urban
environment (Van Mechelen 2015).
Reduced plant mortality also works out
to be much cheaper in the long term
as plants do not need to be regularly
replaced!
Negatives of irrigation
Irrigation, when used carefully, is very
effective at helping plants establish and
survive extended dry spells. However,
when used excessively, irrigation
can lead to poor quality green roofs.
Green roofs are designed to be harsh
environments to prevent excessive
plant growth and ingress of weed
species. Excessive irrigation leads to
certain plant species (grasses, tree
seedlings) dominating and pushing
other more desirable species out. See
Figure 2 (above) for an example of an
inappropriate irrigation system on a
green roof in the UK. This system was
too small to cover the whole roof and
was set on a regular timer, which had
over-irrigated the roof for a number
of months. Species diversity was
significantly less in this area and had
Continued on page 16 >>>
www.greenscapemag.co.uk • GREENSCAPE WINTER 2022 15

ACADEMIC CORNER
>>> Continued from page 15
promoted a much less species-diverse
habitat.
Another example is provided in Figure 3
(right) which shows the massive effect a
dripping pipe can have on vegetation. In
this instance a tap had been leaking for
a couple of years on an extensive roof,
leading to a very different vegetation
composition in this area.
Methods of irrigation
Water can be applied in a number of
ways to a green roof. A number of
these were compared in an excellent
trial by Rowe et al. 2014. The authors
compared overhead sprinklers, drip
lines and sub-surface emitters in a
variety of green roof settings. In this
trial, overhead irrigation seemed to be
the most effective at encouraging plant
growth. Due to the coarse nature of
green roof substrate, the wetting front
of sub-surface and surface drip lines
did not cover the whole green roof,
resulting in patchy growth. However,
the addition of a water retentive fabric
did help to improve the effectiveness of
both sub-surface and surface drip lines
by retaining more water and helping to
more evenly distribute it
(Rowe et al. 2014).
Blue-green roof subsurface
A more efficient sub-surface irrigation
method combines the drainage layer of
a green roof and the water storage of
a blue roof. This means that drainage
water from the green roof is retained
and can be easily reused. An additional
benefit is the much greater amount
of stormwater retention, reducing
potential flooding downstream.
Generally, this involves passive capillary
wicking of water from the storage tank
into the substrate via a water retentive
fabric which helps to evenly distribute
water. This type of system has been
shown to be very effective at irrigating
extensive green roofs, allowing a
reduced substrate depth and providing
Above: Figure 3 shows the huge impact a dripping pipe can have on vegetation.
large amounts of evapotranspiration,
without the need to use additional
water sources (Cirkel et al. 2018),
although this type of system can also be
topped up with other water sources if
captured rainwater runs out.
Smart systems
Irrigation controls are also becoming
much smarter. There are plenty of
systems now that irrigate according
to weather conditions, predicted
evapotranspiration and green roof
moisture levels (Bandara et al. 2016).
Care still needs to be taken when
using these to ensure they are set up
correctly and calibrated on a regular
basis. I have seen plenty of examples
where they have gone rogue and
irrigated nonstop for months on end!
Conclusions
• Irrigation is sometimes required on
green roofs in the UK.
• Requirement is likely to increase in
some areas due to climate change.
• Requirement can be reduced by good
green roof design (substrate depth,
type, drainage layer, moisture retention)
and appropriate plant selection.
• Irrigation system is important – some
are much more efficient at providing
irrigation direct to plant, reducing
losses.
• Water source should always be
considered. Use non potable, captured
or recycled water when possible.
• Excessive irrigation should be avoided
at all costs. Irrigation should be viewed
as a backup and only used to keep
roofs alive. This advice is specific to UK
climate.
• Irrigation system can be combined
with stormwater storage and passively
used to irrigate the roof.
• The green roof system needs to be
thought of carefully as a whole system.
Irrigation should not be considered at
the end as a passing thought to tack
onto the design.
Contact
Dr Tom Young
E: tomyoung@tep.uk.com
Tweet: @DrGreenRoof
16 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

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ROOFING TILES

GREEN ROOFS PLANT SELECTION
GROWING RESILIENCE:
PLANT PLASTICITY AND VARIATION FOR
CLIMATE-SMART GREEN ROOFS
By Dr. Elisa Olivares Esquivel, Lecturer in Planting Design, Department of
Landscape Architecture, at the University of Sheffield.
In the autumn issue of Greenscape,
Dr. Tom Young wrote the first part of
a very insightful article about green
roof challenges in the face of climate
change and the different elements
that can be tuned to achieve resilient
systems.
Plant selection is one of these elements
that goes a long way to future-proofing
the roof and a critical process that is
worthy of far more research. There
are plenty of green roof mixes on the
market, with plants suitable for many
different types of roof. However, with
the impact of climate change, some of
the species that work today may not be
optimal in the future.
Broader plant palettes
These days we often hear that we
need to work not only with broader
plant palettes of species, but also more
diverse plant material with greater
plasticity. These sources of natural
variation (and artificial selection) could
be obtained either by responsibly
and sustainably collecting plant
material from the wild, especially from
distinct populations, or by breeding
drought resistant plants, for example.
Nevertheless, before starting with these
endeavours we need to understand
what these terms mean and their
implications for climate resilience and
adaptation. Plasticity can have different
meanings depending on the discipline
or the context in which we are studying
the plants, for example ecology or
molecular biology.
The concept of plasticity
To clarify the concept of plasticity, Rob
Brooker and his team (2022) explained
how the concept can be applied in crop
breeding. This can be applied to plant
breeding as a whole or plant hunting
and screening for green roofs and / or
green infrastructure.
Brooker explains that one of the most
often applied forms of the term is
phenotypic plasticity, which often refers
to “changes to phenotype in response
to changes in environmental conditions”
(2022). Phenotype, according to
Scitable by Nature Education (2022),
“refers to the observable physical
properties of an organism; these
include the organism’s appearance,
development, and behaviour.”
This means that a plant with a high
phenotypic plasticity could respond
to drought by changing the size of
its leaves, reducing the number of
stomata, and generating a greater
number of offshoots for vegetative
propagation, for example. The plant
can adapt appropriately for its survival.
Phenotypic plasticity can be expressed
in a lower or higher degree in traits,
i.e. “a morphological, physiological, or
phenological feature of an individual
plant that is measurable” (Brooker
et al. 2022) in plants from particular
locations.
In research exploring the plasticity of
Fragaria vesca to drought, clones of
material from different locations of
the French Pyrenees and Alps were
tested in different moisture regimes. It
was found that flowering and runner
production from plants from south
facing slopes were maintained in low
moisture conditions in comparison
with material from north facing slopes,
which had reduced or no capacity for
producing them (De Kort, 2020). This
is found in a higher degree according
to gradient and aspect, more than
to elevation. There is tremendous
variation within species dependent on
a plant’s origins and this can be utilised
for resilient plant selection.
Building-in resilience
The take-home message here is that for
our urban green spaces to survive the
onslaughts of extreme weather events
brought about by the climate crisis, we
need to build-in resilience to our plant
selection now. That resilience comes
from diversity: in the number of plant
species and within-species varieties,
such as ecotype. As with our food
systems, reliance on the same small
number of species and cultivars makes
us increasingly vulnerable to the effects
of climate change and the pests and
diseases that come with it.
Contact Dr Elisa Olivares
Esquivel
Email:
elisa.olivares@sheffield.ac.uk
18 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

Updated GRO Code
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From the publishers of

GREEN ROOFS MAINTENANCE
GAINING THROUGH
MAINTAINING
The experts at Eco Green Roofs (EGR) outline the important
maintenance steps you should take to maximise the
performance and ensure the longevity of your green roof.
To ensure their aesthetic
appearance, design
functionality and
environmental benefits are
maintained, it is important that
regular maintenance of green
roof systems is undertaken.
At Eco Green Roofs, we
recommend that regular
maintenance be carried out at
intervals appropriate for the
type of living roof; generally
twice per annum for sedum and
biodiverse roofs, and between
3 and 6 times per annum for
fully developed wildflower blankets.
Given the investment made in the
design and installation of a green
roof, it is important that the system
delivers its full life-cycle potential of
both commercial and environmental
benefits. A well-managed and regular
maintenance programme will ensure
longevity of performance and an
economic and environmental/social
return.
The main considerations to ensure the
ongoing performance of a living roof
are:
• Free flowing and unrestricted roof
drainage
Regular maintenance of roof outlets
and drainage inspection chambers will
ensure free flowing and unrestricted
roof drainage. It is vital that an excess
build-up of rainwater is not retained on
the roof to harm the living roof. Excess
water will weaken root systems and
allow invasive species to take over.
• An adequate amount of nutrients
The correct amount of nutrients in a
living roof is important to help maintain
strong and consistent vegetation
growth and coverage across the
whole roof area. A lack of nutrients
will eventually result in bare patches
across the roof and will limit the
species capable of living in the system.
Conversely, if it’s too nutrient rich, it will
encourage excessive vegetation growth
which will require trimming and cutting
back to acceptable levels.
• Control of all spent vegetation, and
undesirable and potentially invasive
species
To maintain the balance of both species
and nutrients it is important to monitor
development of the plants. This involves
controlling excess growth and regularly
removing dead material and excess
vegetation to avoid impeding drainage
and leaving excess biomass on the roof
which can upset the nutrient levels in
the substrate and spoil the aesthetic
look and design performance.
At this time of year it’s
particularly important to pay
attention to these elements.
Leaves are falling and although
some sedum and late flowering
wildflowers are still in bloom,
there will also be many deadheads.
All of this excess
vegetation should be removed
from the living roof areas. Any
spent vegetation left over the
winter can add unwanted biomass
to the roof as it rots down,
causing nutrient levels to become
too high. This is particularly
important to avoid on biodiverse roofs
which need low nutrient systems. If leaf
guards or inspection chambers are not
in place over outlets, these need to be
checked before the winter to make sure
they are not blocked with leaf litter,
which could cause leaks. It’s also the
time of year when permanent irrigation
systems need to be drained down, so
that there is no water left in external
pipework over the winter – otherwise
this could freeze and burst.
If you don’t already have a maintenance
contract in place, now is a perfect
time to have your green roof tidied
and its condition checked, and a plan
put in place for when the roof starts
its growth again in the spring. Regular
maintenance visits really can make a
difference to the year-round health and
appearance of your living roof.
Scan the QR code to speak
to one of our Eco experts
20 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

TAKE YOUR
ROOFING BUSINESS
TO THE NEXT LEVEL WITH NFRC
Technical advice, the industry quality stamp and fantastic
profile-raising opportunities—for all roofing disciplines
NFRC sets the highest
standards for work across
all roofing and cladding
disciplines. But we’re much
more than the industry’s quality
assurance stamp. Membership
of the trade association offers
contractors and suppliers a
range of powerful technical
and commercial advantages.
These include a profile on our website
and directory listing, making your
business easier for clients to find. Plus
exclusive access to technical support and
updates, an exclusive health and safety
app, and advice on training provision.
For suppliers, key benefits include
numerous opportunities to engage with
roofing contractors all over the country.
And as the voice of the roofing sector,
NFRC makes our members’ views
heard where it matters most. We work
with government, standards bodies
and training providers to promote the
interests of the industry, and of the
construction market as a whole.
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MYTHBUSTERS
MYTH: DEEPER SUBSTRATE MEANS
MORE EXPENSE
Fact: Optimising substrate depth leads to enhanced benefits and greater sustainability. The experts
at GRO explain more...
When designing any structure,
build costs will always need
to be a consideration. But
rather than think in terms of initial
expenditure, think about lifetime value
for money. The purpose of this article
is to encourage you to think about
future proofing the green roofs you are
designing, installing and maintaining,
rather than viewing them as a boxticking
exercise.
Let’s start by reviewing the functions of
the substrate layer on a green roof. The
most obvious is, of course, to sustain
life and give the plants somewhere to
grow whilst also providing a home for
nature. The substrate is also an intrinsic
factor in stormwater management,
thermal performance, protecting the
waterproofing from UV and mechanical
damage, fire protection and creating
wildlife habitat.
Substrate installation.
Image courtesy of
Bridgman & Bridgman
On a less positive note, some green roof
designers are tempted to skimp on the
substrate layer to reduce the loading
and cost. However, this is a mistake that
would be more difficult – and expensive
– to rectify once the structure is built
and the green roof installed.
The benefits of deeper substrates
include:
• Increased ability to retain water and
help mitigate the risk of flooding.
• More room for plant roots to develop,
therefore vegetative layer is more
robust.
• Allows a wider choice in the planting
pallet enabling facilities managers to
adapt the vegetative layer should local
conditions alter due to climate change.
• Happier plants lead to a self-sustaining
community which needs lower amounts
of irrigation and fertiliser applications,
saving on some maintenance costs.
• More effective at protecting the
waterproofing from daily variations in
temperature.
• Deeper substrate also helps moderate
temperatures within the building.
Deciding on substrate depth
The GRO Code recommends that
green roof substrate depth should be
a minimum of 80mm for a relatively
simple extensive sedum roof. However,
don’t limit your planning to the plant
palette you intend to use at the point
of installation. Will the conditions on
this roof still be the same in a decade’s
time? Maybe a bigger building will have
appeared next door making this space
too shaded for shallow rooted sedums.
What will the local climate be like?
Will 80mm depth of substrate still be
enough to absorb enough water from
a severe rainfall episode in a changing
climate? When planting needs to evolve
along with changes that are beyond
your control, a deeper substrate will
keep your options open.
When deciding substrate depth, try
22 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

to consider all of the benefits
that the substrate offers.
Areas of deeper substrate
interspersed with areas of
shallower substrate will allow
you to not only spread costs by
concentrating the loading on
stronger areas of the building,
whilst creating different habitats;
Imagine a wealth of different
plant species enjoying different
conditions. You can create
berms, humps and hollows and
even engineer potential nesting
sites for bee species that like to
burrow. From an ecological point
of view, variable topography is a
wonderful thing.
Substrate depth and reducing
the cost of green roof
ownership
A good green roof is designed to
perform long after the installers have
left the building. And, in order for that
to happen, the vegetative layer of the
roof must be maintained – and this
must be budgeted for.
Plants with insufficient room for their
roots, too many or too few nutrients,
inadequate water or the wrong
amount of sunlight will not thrive
and environmental and aesthetic
performance will suffer. This is also
important on bio-solar green roofs
where the activity of healthy plants
helps to optimise the performance of
PV panels.
A deeper substrate layer has been
shown to help plants become more
resilient to frost and to drought. It also
allows a greater degree of biodiversity
so that if any species struggle with a
particular season, there are always
others that will thrive. In any wildflower
meadow at ground level, the plant
species mix will change every year
depending on weather conditions, and
the same effect can be seen on living
roofs, which are subject to even harsher
extremes.
Above: substrate depth recommendations.
Deeper substrate will retain more
water for longer which eases
pressure on drainage systems from
stormwater runoff and supports the
vegetative layer reducing plant losses.
Better plant health means stronger
evapotranspiration and cooling effects,
maintains a great aesthetic, and all
of the associated wellbeing benefits
for people overlooking the roof. It
also means that unwanted plants will
be hard pressed to find the space to
establish on the roof, thus lowering the
maintenance requirement.
Another aspect of green roof
maintenance that is costly for the
owners of shallow substrate sedum
roofs but free for owners of deep
substrate roofs is fertiliser. Because
green roof substrate is necessarily
low in organic matter, you need
enough substrate to get enough soil
microbes to fix nitrogen (plant food)
from the air. With a deep substrate,
plant nutrient levels are usually quite
self-sustaining and will prevent plants
from getting too large and sappy. On a
shallow substrate additional fertiliser
may be needed (this should only be
applied when downpipes are isolated
from the main sewage system -
(please refer to section 5.1.2 of
the GRO Code).
The cost of getting it wrong
Ultimately, the price you pay for
a green roof has to be in line
with your long-term objectives
for that project. If you are
designing a structure that is
to be sustainable, valuable to
the local environment, resilient
to climate change, offer great
PR and wellbeing benefits and
boost biodiversity, then a green
roof is a must. It is more costeffective
to build it properly
in the first place than to cut
initial installation costs and then
make changes ten years down
the line.
The singer Meatloaf sang that the two
saddest words in the English language
are “If Only”. If you are designing or
installing green roofs, don’t let that be
your legacy!
In summary
The deeper the substrate layer on your
green roof design, the stronger the
structure beneath it will need to be and
of course there are associated costs
with that.
However, with careful design and
installation, those costs will be offset
by more manageable maintenance,
enhanced benefits and a beautiful roof
that will go down in history as being an
asset to the environment.
Contact
GRO
www.greenrooforganisation.org
Tweet: @RoofGro
www.greenscapemag.co.uk • GREENSCAPE WINTER 2022 23

GREEN ROOF SUBSTRATES
WHAT LIES BENEATH?
We talk substrate composition with Wallbarn and partner
company Sedum Growers, and hear about the growing media
they’ve developed for the M-Tray system which encourages plant
growth and complies with all relevant standards...
A
farm tucked away
in the Hampshire
countryside has been
leading a quiet revolution
in the development of high
quality, low organic and peatfree
substrate that meets fire
ratings and follows GRO Code
guidance.
It could, perhaps, be
considered the holy grail of
green roof growing media,
delivering an optimum blend
and supply of slow release
nutrients coupled with great
moisture control qualities,
enabling plants to flourish
throughout the life of the
roof. The mix represents a
fine balancing act between
the basic elements of
the substrate – compost,
lightweight aggregate and coir
– and the need to achieve compliance
with BS 8616:2019, Approved Document
B, the GRO Code and the B ROOF t(4)
fire rating.
And it’s only available with the awardwinning
M-Tray modular green roof
system from Wallbarn. The substrate
has been developed for the British
producer by partner company Sedum
Growers in conjunction with renowned
soil scientist Susie Holmes, a specialist
in horticultural growing media and soil
management.
Composting
Producing this BS-compliant substrate
relies heavily on the quality of the green
compost and it’s here that the greatest
of care has been taken to ensure that
sedum and wildflower plants in M-Tray
are grown in the highest quality media,
as Sedum Growers’ joint Managing
Directors David Holloway and Keith
Pegren know. David explained: “For us,
a lot of the commercially available Pas
100 compost is of unknown quality.
It might contain weeds or hormonal
herbicides which don’t breakdown in
the composting process. We therefore
manufacture our own on site using
local, known sources of raw materials.
We control the whole process from start
to finish, which can take in excess of a
year and produces a very high quality
product.”
So if you think your delivery of
M-Tray modular trays smells sweetly
fragrant and herby, then you may
well be right, for one ingredient used
Green roof substrate
components
in the compost is discarded
matter from a local business
producing chamomile and
other essential oils. This high
nutrient waste stream meets
David and Keith’s exacting
standards because they know
its provenance and quality,
and it has already been heated
to high temperatures, killing
weeds etc.
Sourcing these raw materials
ultra-locally – usually within 20
miles – also means Wallbarn
minimises road miles.
Other carefully selected
agricultural waste is combined
into the mix, which is then
left to compost. “It’s quite a
complex process,” explained
Keith. “It has to be warm
enough to kill weeds etc.
so we continually check
the temperature, and the chemical
composition of the final compost is
key. Chemicals released during the
composting process create salts, which
can be harmful to plants so they have
to be allowed to leach out. We carry out
electro conductivity tests to measure
salts content and only release the
compost for use when it has physically
cooled down sufficiently, and salts are
at a safe level.”
To complete the Wallbarn substrate, coir
and Lytag or Leca are combined with
the compost:
Coir: a lightweight, natural by-product
of the coconut industry used in
Continued on page 26 >>>
24 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

GREEN ROOF
Above: Wallbarn’s M-Trays filled with substrate (left of image) and waiting to be filled. Inset: Sedum trays. Below: The composting process.
>>> Continued from page 24
M-Trays to lighten the substrate
mix and introduce fibres that lock
in moisture and nutrients. In use,
interaction between the green
compost and the coir gives a
slow release of nutrients over an
extended period of time.
Lytag: a lightweight ballast which is
a waste product from power station
waste.
Leca: an expanded clay which
is also a waste product and super
lightweight/bulk forming. The roots
of sedum and wildflowers grip the
particles to bind into the substrate and
support the whole green roof.
The GRO Code advises 50% non-organic
content within the substrate and Wallbarn
achieves this by including Lytag/Leca
pellets, which it sources in the UK. That
both the coir and Lytag/Leca are waste
materials from other industries is no
coincidence; Wallbarn says it strives to
make its M-Tray system as environmentally
friendly as possible within the bounds of
performance and regulatory compliance.
The green red line
David and Keith are also very clear
that peat has no place in any compost
Sedum Growers produces: “It is a red
line for us and has been for the last 10
years. We were determined to phase
out peat rather than wait for the
legislation to change,” Keith said.
The legislation he refers to is aimed
at protecting peatland habitats and
meeting net zero targets, with the
government set to ban the use of peat
in horticulture retail by 2024 and by
2028 for commercial growers.
Rigid adherence to high quality and
environmental responsibility is
an ethos driven by Wallbarn, as
Director Julian Thurbin explained:
“Wallbarn goes above and beyond
legislation and guidance relating
to green roofs. We’ve been at the
forefront of many industry changes
and always strive to physically test
ingredients to ensure they perform
as we wish, using Warringtonfire for
fire tests and STRI for growth tests.
“M-Tray exceeds all regulations by
a significant degree. Our ethos is
to provide customers with industryleading,
healthy green roofs that
thrive throughout their lifetime, meet
regulatory and industry standards and
are as eco-friendly as possible.”
Contact
Wallbarn
www.wallbarn.com
Tweet: @wallbarn
26 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

SIKA NOW OFFERS A COMPLETE
GREEN ROOFING SYSTEM
WITH ROOTS LIKE OURS, IT WAS
THE NEXT NATURAL STEP
Building on our reputation in roofing, Sika’s complete
green roofing system provides many sustainable
benefits. And on one project, it has even provided
a grazing area for a flock of Dutch Spotted Sheep,
who help reduce maintenance costs.
Sika’s complete green roofs help to manage storm
water, improve the building’s thermal performance
and enhance biodiversity in nature.
SikaRoof ®
Wildflower
Blanket UK
SikaRoof ®
Substrate
Bio-diverse UK
SikaRoof ®
Rigid Drainage
Layer 20 UK
SikaRoof ®
Protection Fleece
P-225 UK
WOULD YOU LIKE TO KNOW MORE?
Email enquiries@uk.sika.com
Visit www.sika.co.uk/greenroof

SOLAR PV RESIDENTIAL PROJECTS
THE YEAR WHEN PART L
BECAME REAL!
By Stuart Nicholson, Roof Systems Director at Marley.
This year has been a pivotal
point in the nation’s journey to
decarbonise and move towards
the net zero target set for the middle of
the century.
The summer months finally saw the
introduction of amendments to Part
L of the Building Regulations. The
changes have been implemented to
ensure newly built homes produce 31%
lower carbon emissions. With houses
creating 40% of the UK’s greenhouse
gases according to the Climate Change
Committee, by tackling home-related
emissions in this way considerable
progress can be made.
Various sectors within the construction
industry are now grappling with the
implications of Part L and how they
will ensure compliance with the
requirements going forward. Many
are already looking at the benefits
that opting for renewable energy
solutions can deliver in the fight to
reduce household emissions and
tackle tangible consumer challenges
associated with energy consumption
and cost.
Experts have stated that improvements
to energy efficiency and lower
emissions levels simply can’t be
achieved just by enhancing the building
fabric on its own. That is why an
innovative combination of renewable
technology is being favoured.
Over the short term, bringing
together solutions such as solar PV
on roofscapes is one of the easiest
and most cost-effective ways to
satisfy the Part L carbon reduction
targets. Not only does it make use
of currently available and proven
green technologies, but it also opens
a pathway for homeowners to access
dependable, sustainable, and costefficient
sources of energy.
Looking ahead to the future
The specification of solar PV on
roofscapes is now increasingly gaining
traction as an immediate and effective
answer. Aside from the obvious
Continued on page 30 >>>
Marley SolarTile is an
integrated PV roof solution
28 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

Technical support
Roofing experts on-hand to offer help and advice
Assured standards
Meets all British Standards and regulations
High-quality components
Tested for maximum performance, meaning no call backs
Estimates & fixing specs on demand
We’ll help you create them on site and on the go
Comprehensive roof solution
Easy installation with tried and tested compatible components
Need a complete
roof system?
We’ve got you covered.
With all elements brought together from a single
source, you can be confident that everything
will work together perfectly – and that high
performance is all backed up with a 15-year
system guarantee. Find your peace of mind.
marley.co.uk/roofsystem

SOLAR PV RESIDENTIAL PROJECTS
>>> Continued from page 28
attraction as a renewable energy
source, it can also add overall value to
properties. According to Solar Energy
UK, adding solar PV can increase the
market value of a house by around
£1,800.
In addition, awareness of solar is also
growing across the construction sector,
with 40% percent of housebuilders,
specifiers and architects recently polled
by Marley saying they are already aware
of the positive impact solar PV can have
as a sustainable technology within the
overall building fabric.
Whilst specifiers, housebuilders and
consumers may have concerns about
the appearance of bulky, on-roof solar
panels, the latest integrated PV roof
systems now offer a more visually
appealing, cost effective and easier to
install option.
Replacing a section of roof tiles, an
integrated PV solution such as Marley’s
SolarTile provides a sleek aesthetic and
acts as a seamless part of the overall
roof. This type of solar panel can also
be installed at the same time as the
rest of the roof tiles, without a specialist
contractor.
Marley SolarTile can also come as a key
component of a fully integrated roof
system from a single source supply
with the substantial offer of a 15-year
guarantee providing peace of
mind to specifiers and home
purchasers.
With electric charging points on new
builds, and homeowners looking to
embrace green technologies such as
heat pumps and solar on the roofscape,
specifiers are responding and seeking
new solutions.
Doing so also helps safeguard people
against energy price concerns as
they use cleaner, greener, and
cheaper power.
For more information
about Marley SolarTile visit:
www.marley.co.uk/solar
Tweet: @MarleyLtd
30 GREENSCAPE WINTER 2022 • www.greenscapemag.co.uk

THE GRO GREEN ROOF CODE 1
Green Roof Code of Best Practice
incorporating Blue Roofs and
BioSolar Applications
Anniversary Edition 2021
Photo: ABG Limited
THE GREEN ROOF ORGANISATION
THE G
ROO
Green Roof
incorporatin
BioSolar Ap
Anniversary
Photo ©ABG Ltd
The Green Roof Organisation (GRO) represents companies, organisations and
people involved in, or interested in, nature-based roof solutions that help our
towns and cities mitigate and adapt to the effects of climate change whilst
making them nicer, healthier places to live.
GRO members positively contribute to the delivery of living green and blue roofs
that support nature, provide amenity, attenuate rainwater and generate solar
energy, helping ensure no roof goes unused.
Whether you are active in ecology, design, specification, installation or the
maintenance of green and blue roofs, join GRO and help make where we
live and work greener.
Further information:
E: membership@greenrooforganisation.org
COMING
SOON
THE GRO GREEN
ROOF CODE
W: www.greenrooforganisation.org :
GRO CODE
@ROOFGRO
@WGRD2021

WATERSHED
MOMENT.
Meeting Carbon Net Zero and
the wider challenges of climate
change needs innovation, vision
and a fundamental change to
urban development.
A breakthrough in water
management will help
unlock the solution - Green
Urbanisation.
Green Urbanisation
• Utilises surface water to introduce and sustain urban green assets
• Promotes biodiversity and ecological regeneration
• Reduces potable water demand and energy consumption
• Delivers multi-functional environmental, health and wellbeing benefits
• Enhances resilience to flooding, drought and population expansion
Unlock the future at polypipe.com/watershed
Civils & Green Urbanisation