Autumn '21

GREENSCAPE 

Ensuring Best Practice for Green Roof & Solar PV Projects MAGAZINE 

AUTUMN 2021 

Maintenance Focus 

Green Talk: Q&A 

Policy Push 

News, Views and Projects 

Mythbusters: Blue Roofs 

Project Focus: Live Lab 

In collaboration with the Green Roof Organisation

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GREENSCAPE 

IN THIS ISSUE... 

Matt Downs 

Editorial Director 

mattdowns@media-now.co.uk 

07963 330774 

www.greenscapemag.co.uk 

Whilst those involved in the many disciplines and sectors that make up the green 

roof industry are well aware of the benefits that green roofs and associated 

systems bring to buildings and the local environment they occupy, taking this 

message further afield to external stakeholders is the only way to ensure continued 

growth for green infrastructure projects. 

This point is well made by Paul Collins, a GRO Board Member and planning and 

development surveyor who works for Nottingham Trent University, who looks at the 

opportunities for growth within green infrastructure through local planning policy 

following proposed changes at national level. As Paul explains: “It is important for green 

roof professionals to understand the planning tools that influence the uptake of green 

roofs in order to engage positively with relevant authorities and promote the industry 

successfully.” Paul expands on the changes and opportunities available on page 24. 

Expanding on the theme of collaborating for the good of the green roof industry, Maggie 

Fennell Wells, of Boningale Ltd. and also a GRO Board Member, explains the importance 

of interacting with a wide audience to ensure the best outcomes for green roof projects. 

As Maggie explains in her column on page 10: “A diversity of participants with a shared 

goal of promoting the responsible implementation of successful green roofs ensures a 

steady, realistic journey towards better understanding and quality delivery.” 

Elsewhere in this issue, we talk Bee Bus Stops in Leicester with Wallbarn (page 12); take a 

look at the Live Lab project in Milton Keynes (page 28); Nick Day of Optigrun addresses 

maintenance issues for green roofs (page 30); whilst Marley’s Stuart Nicholson outlines 

advice for solar PV projects (page 40). So read on for all this and much more! 

Front cover image: Green roof at Sharrow School, Sheffield 

(Bauder). Read Paul Collins’ article on green roof policy and 

the opportunities for the sector (page 24). 

GREENSCAPE 


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p14 

Academic 

Corner 

Dr Tom Young 

of STRI Group 

talks health and 

well-being. 

p18 

Green Talk: 

Q&A 

Michelle Wright 

of ICB (Projects) 

Ltd. tackles our 

questions! 

p22 

Blue Roof 

Mythbusters 

Anthony Barnett 

of ABG Ltd. 

dispels the latest 

myths! 

In his latest column, Dr Tom addresses 

the evidence that links the positive 

impact of green infrastructure and 

systems on the mental health and 

overall well-being of individuals. 

Page 14 

Michelle gives her thoughts on the 

uptake of green systems, looks back 

on interesting projects, and explains 

why there’s still more to do to raise the 

profile of green roofs and systems. 

Page 18 

Anthony looks at the key considerations 

around Blue Roof projects, despelling 

the myths concerning the structural 

loading implications and ‘storm water 

storage’ role of Blue Roofs! 

Page 22 

www.greenscapemag.co.uk • GREENSCAPE AUTUMN 2021 3

Contents 

NEWS 

06 Top services Take a look at the 

undulating green roof at Leeds 

Skelton Lake Motorway Services 

from ABG and Geogreen Solutions 

that scooped a BALI award 

08 Blue focus for ACO A new CPD 

webinar from ACO focuses on 

Blue / Green Roof Design challenges 

and best practice 

09 4 top projects Which green roof 

projects have been shortlisted for 

this year’s UK Roofing Awards? 

GREEN ROOFS 

10 Connected network Maggie 

Fennell Wells discusses the 

importance of collaboration within 

the green roof supply chain 

24 Policy push Paul Collins says 

new Design Codes and a new 

Environment Act should be a real 

boost for green roofs 

28 Live Lab project Julian Thurbin 

of Wallbarn discusses a great green 

roof project involving many GRO 

members in Milton Keynes which is 

providing benefits on so many levels 

4 GREENSCAPE AUTUMN 2021 • www.greenscapemag.co.uk

GREENSCAPE 

SOLAR PV 

40 Power-up Stuart Nicholson 

provides his six key considerations 

to ensure a smooth PV project, 

including choosing the correct 

system, considerations around 

property and roof suitability, and 

advice regarding permitted planning 

rights 

REGULARS 

14 Academic Corner Dr Tom Young 

looks at the link between green 

infrastructure and systems on 

health and mental well-being 

18 Green Talk Michelle Wright of ICB 

(Projects) Ltd. tackles our Q&A, 

discussing the challenges and 

opportunities within the sector 

22 Mythbusters Anthony Barnett 

dispels the myths around the 

structural loading implications and 

storm water storage function of 

Blue Roofs 


News 

GREENSCAPE 

A FURTHER BOOST FOR 

SOLAR IN THE UK 

Solar Energy UK has welcomed the 

confirmation that solar power will be 

included in the latest round of the 

Contracts for Difference (CfD) scheme. 

Solar power will be eligible to 

compete for up to 3.5GW of 

electricity generation capacity in 

the key renewable energy auction, 

due to take place in December 2021. 

Solar’s inclusion reflects analysis in 

Solar Energy UK’s Lighting the way 

report, which details the contribution 

CfDs and solar power can make to 

the UK’s climate change targets. 

Chris Hewett (below), Solar Energy 

UK Chief Executive, said: “This will 

give a further boost to solar in the 

UK, which has already built 730MW 

of solar energy projects in the last 

12 months. There are over 4GW of 

projects that will be eligible to bid for 

these contracts.” 

He added: “The UK needs to triple 

its solar capacity to 40GW by 2030 

to stay on track for its own carbon 

targets, so we welcome this level of 

ambition from the Government. This 

commitment needs to be sustained 

and extended to rooftop solar, to 

create another 13,000 new green 

jobs.” 

MOTORWAY SERVICES WILDFLOWER GREEN ROOF SCOOPS BALI AWARD 

ABG Geosynthetics and Geogreen 

Solutions, its BALI affiliated installation 

partners, have been recognised with 

a prestigious British Association of 

Landscape Industries (BALI) award for 

their work on the new Leeds Skelton Lake 

Motorway Services. 

The services sits adjacent to a 40,000m 2 

area of country park, so to ensure the 

development blends in to the surrounding 

lakeside and to minimise the visual impact 

of the development, the main 5,277m 2 

amenity building features an over-arching, 

undulating green roof. 

The wildflower roof system was delivered 

by ABG Geosynthetics and their 

installation partners Geogreen Solutions. 

A member of the BALI judging team 

visited the site at the beginning of July, 

and then convened with other members 

of the panel over three days in August 

to assess the entries and determine the 

winning schemes. 

Following a record number of entries this 

year, Geogreen was announced as winner 

in the Category of Roof Garden project 

with a value over £500K. 

Geogreen’s work encompassed all aspects 

of the installation for the 11 separate 

ribbon areas and the judges recognised 

the contribution the roof design makes 

to enhancing the biodiversity of the site, 

providing a significant area of native 

grassland for local insect and bird species. 

The green roof also plays an important 

function as part of the development’s 

overall sustainable drainage strategy, 

absorbing rainwater and minimising 

surface water run-off, with as much as 

95% of rainfall naturally absorbed into 

the vegetated surface. The vegetation, 

growing media and filtration fabrics within 

the green roof construction also helps 

filter dust and pollution from the air and 

rainfall, thus reducing the amount of 

chemicals and pollutants that reach the 

surrounding river networks. 

This project has also been shortlisted 

in the Green Roof category of the UK 

Roofing Awards. 

The BALI awards event is being held at 

the JW Marriott, Grosvenor House Park 

Lane Hotel on December 3. 

Read more on this project at 



News 

MAINTAINING STANDARDS 

Green-tech says it is delighted to 

have been awarded ISO 9001:2015 

and ISO 14001:2015 status for the 

10th year running. 

ISO 9001 and ISO 14001 are two of 

the ISO’s most well-known standards 

and are said to be implemented by 

more than a million organisations in 

over 170 countries. 

ISO 9001 is a Quality Management 

System (QMS) which gives 

organisations a systematic approach 

for meeting customer objectives 

and providing consistent quality. 

ISO 14001 is an Environmental 

Management System (EMS) 

for measuring and improving 

environmental impact. 

Mark Wood, Business Development 

Director, commented: “We take our 

corporate responsibility very seriously 

and working within the ISO framework 

helps Green-tech to deliver high 

levels of business performance and 

customer service. It is not an easy 

thing to achieve, and we are one of a 

handful of landscaping companies with 

this accreditation to our name, so I am 

delighted that we met the audit’s indepth 

scrutiny to retain our ISO status. 

We hope it gives our stakeholders, 

customers and suppliers independent 

reassurance of our commitment to 

delivering quality products and service, 

and our pledge to reducing our 

environmental impact whilst becoming 

a more sustainable organisation.” 

ACO SET TO ADDRESS BLUE/ 

GREEN ROOF DESIGN WITH CPD 

ACO’s new RoofBloxx rainwater 

attenuation system is designed 

specifically as a roof drainage layer 

for use on Blue, Green and Blue/ 

Green roof applications to store 

rainwater at source and to control 

surface water run-off. ACO’s patent 

pending solution separates the 

competing drainage requirements by 

engineering an elevated structural 

attenuation system that operates 

independently of the flat roof 

drainage system, allowing both storm 

eventualities and systems to be 

engineered to known standards and 

best practice. 

You can learn more about Blue/ 

Green Roof design in ACO’s latest 

CPD webinar which the company 

says will challenge your perception 

about Blue/Green Roof design. 

ACO says with the drive to mitigate 

the effects of climate change and 

deliver net zero emissions, cities 

around the world are writing into 

their development plans the need 

for more sustainable construction 

methods, and this presentation will 

explain the role of Blue/Green Roofs 

in the creation of sustainable urban 

environments, covering the key 

design considerations. 

With key elements of interest for 

architects, roofing contractors, 

civil and building engineers, ACO 

says this webinar CPD will explain 

the pros and cons of different roof 

types and provide participants with a 

comprehensive understanding of key 

drainage design considerations. 

Delivered by Neill Robinson-Welsh, 

ACO’s in-house Blue/Green Roof 

design expert, the session will also 

cover the ‘design dilemma’: how to 

design a Blue/Green Roof which can 

meet the flat roof design standards 

under BS EN 12056-3:2000, and 

meet planning conditions without 

compromising either requirement. 

The event counts as 1 hour of 

CPD. Register at: https://app. 

livestorm.co/aco-technologies/ 

blue-green-roof-drainage-makingsustainable-urban-environments-areality-november21?type=detailed 

Learn more about the ACO system 

www.aco.co.uk/blue_green_roofs 


GREENSCAPE 

SIKA’S NEW OFFERING 

Sika has launched a complete 

Green Roof package, supplying 

both the high performance roof 

waterproofing system and the green 

roof system, all backed by its trusted 

technical and application support. 

Specifiers can now go to Sika’s 

roofing experts for the full spectrum 

of roofing technologies, from hot 

melt structural waterproofing and 

reinforced bituminous membranes 

to single ply and cold-applied liquid 

membranes, depending on what is 

best for the project in question, all 

of which can now be laid with a Sika 

Green Roof system on top. The new 

systems are manufactured in the 

UK and are available in three of the 

most common green roof types — 

extensive, intensive and biodiverse. 

Sarah Peake, Sika’s Sustainability 

Manager, said: “The construction 

of new buildings can play a huge 

role in contributing to the world’s 

sustainability targets and green 

roofs are part of the solution. The 

fact that the green roof market is 

growing by approximately 17 per 

cent per year speaks for itself. 

Thanks to its numerous ecobenefits, 

a Sika Green Roof can 

help architects hit sustainable 

development targets and achieve an 

improved rating from schemes such 

as BREEAM and WELL, which are 

instrumental in helping us build for a 

better future.” 

1 2 

3 

GREEN ROOF FINALISTS FOR UK ROOFING AWARDS ANNOUNCED 

Following a thorough judging process, the shortlisted projects – including the Green 

Roof category – for the UK Roofing Awards 2021 have now been finalised. 

The Roofing Awards will take place as a live event on 5 November 2021 at The 

Intercontinental London – The O2. The awards will be the first live Roofing Awards 

since 2019 after the 2020 Awards event was unable to go ahead due to Covid-19 

restrictions. 

The finalists for the Green Roof category, which is sponsored by GRO are: 

1. Sky Garden’s work on the Ashraya residential project. 

2. ABG Geosynthetics and Cawston Specialist Roofing’s work on Leeds Skelton Lake 

Motorway Services. 

3. Malone Roofing’s work on The Centre for Agricultural Biosciences International. 

4. BriggsAmasco’s work on the Williamsgate Water Treatment Works. 

The winners of the 2020 UK Roofing Awards will also be showcased at the 2021 event 

through a dedicated short film produced by the broadcast television producer Dave 

Packham. 

Voting for the UK Roofing Awards ‘Industry Choice’ category, sponsored by Radmat 

Building Products, is also now open. 

Everyone is now able to vote for their favourite finalist through an open vote via the 

UK Roofing Awards Voting Platform at https://nfrc.awardsplatform.com. There is 

one vote per person. 

4 

Tables for the event can be booked at www.nfrc.co.uk/uk-roofing-awards/attend 

NFRC says it would like to thank headline sponsors Radmat Building Products, as well 

as the following sponsors for making the awards possible: SIG Roofing, BMI, Axter 

Waterproofing Systems, Chandlers Roofing Supplies, Cromar Building Products, CUPA 

PIZARRAS, EJOT, Fakro, GRO, Marley, Metal Solutions, QANW, Recticel Insulation, 

Siderise, Sika, TN International and W J Horrods. 

Green Roof images above; 1. The Ashraya project; 2. Leeds Skelton Lake Motorway 

Services project; 3. The Centre for Agricultural Biosciences International; 

4. Williamsgate Water Treatment Works. 


GRO NETWORKING 

THE CONVERSATIONS AT THE HEART 

OF THE GREEN ROOF INDUSTRY 

Maggie Fennell Wells, GRO Marketing Committee Chair, discusses how GRO 

is interacting with the market to ensure conversations and collaboration help ensure 

best practice and outcomes for green roof projects… 

Cross-disciplinary collaboration 

is crucial for successful green 

roofing. Hydrology, civil 

engineering, landscape architecture, 

horticulture and ecology were all 

represented at the University of 

Sheffield’s Green Roof Centre, which 

was my own very first introduction to 

the subject. 

This was a hub where academics 

could bring their separate fields of 

expertise together to look at the whole 

system – in a truly integrated way – in 

order to improve the whole system. 

Then all I had to do was to link that 

research with industry and the practical 

reality through a Knowledge Transfer 

Partnership! 

Since then, there has been huge 

progress in building the foundations 

for the technical integration needed 

in industry to deliver green roofs, 

including three evolutions of the GRO 

Code of Best Practice, the launch 

of successful Green Roof training 

courses with Lantra, and the 

transition of GRO into a 

formal Trade Association 

in 2020. 

GRO promises to 

provide great networking 

opportunities for the whole 

range of different disciplines 

and sectors involved in green roofing, 

linking new-comers and innovators with 

seasoned and experienced members. 

These conversations and debates allow 

us to identify common problems and – 

more importantly – potential solutions. 

A diversity of participants with a shared 

goal of promoting the responsible 

implementation of successful green 

roofs ensures a steady, realistic journey 

towards better understanding and 

quality of delivery. This underpins the 

development of trust and relationships 

between companies and organisations 

that might not normally interact, but 

must understand each other to deliver 

the best environmental outcomes 

possible. 

Left: Maggie Fennell Wells is GRO 

Marketing Committee Chair 

and Product Development 

Manager at Boningale. 

Networking has been one 

of the GRO membership 

benefits that has been 

most difficult to provide 

during the pandemic, but one 

which we have been determined to 

pursue with any means at our disposal. 

GRO led the second World Green Roof 

Day back in June this year, stimulating 

conversations across the world and 

provided an online webinar to launch the 

GRO code with themed zoom breakout 

rooms for more in-depth discussions. 

These online media are likely to stay 

as a widely accessible and inclusive 

part of our engagement activities, 

however we are delighted to be able 

to offer our members a range of 

face-to-face networking opportunities 

as well this autumn. We will now be 

able to celebrate successes together 

at the NFRC Roofing Awards and 

engage newcomers with practical 

demonstrations at Futurescape Show, 

with additional talks planned at shows 

outside London as well. 

Whatever discipline you represent, 

please come and find us to join the 

conversation about green roofing. 

Contact GRO 

email: 

membership@ 

greenrooforganisation.org 

www.greenrooforganisation.org 

Tweet: @RoofGro 


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GREEN ROOFS BUS STOPS 

CITY’S GREEN ASPIRATIONS 

BRING A BUZZ TO BUS STOPS! 

Wallbarn’s work installing living roofs on bus stops in Leicester 

has brought numerous benefits to the city centre... 

Leicester residents and visitors 

may have little idea that an urban 

transformation is taking place just 

a few feet above their heads thanks to a 

ground-breaking initiative to green the 

city and support ecological diversity. 

Two city centre thoroughfares – 

Humberstone Gate and Charles Street 

– have seen 30 new bus stops springing 

up over the summer sporting one key 

distinguishing feature; living roofs. 

Affectionately nicknamed ‘bee bus 

stops’, the shelters form part of Leicester 

City Council’s ambition to be a carbon 

neutral and climate-adapted city by 2030, 

while delivering an invaluable boost to 

the locality’s biodiversity, most notably 

pollinating insects. Such a large network 

of living roofs is a first for a UK city and 

an important step forward in tackling the 

decline of urban greenery, flora and fauna. 

To deliver the bee bus stops, out of 

home advertising and infrastructure 

company Clear Channel UK – operator of 

Leicester’s bus shelters – partnered with 

leading British living roof manufacturer 

Wallbarn to install M-Tray, its awardwinning 

modular green roof system. 

Julian Thurbin, Wallbarn Director, 

explained: “This is an absolutely 

fantastic project, providing the city with 

a ‘bee superhighway’ and all the many 

recognised benefits of living roofs. It’s 

showcased how adaptable the modular 

system is and what can be achieved by 

uniting street furniture and green roofs, 

providing the people of Leicester with 

splashes of greenery that will change 

with the seasons.” 

Wallbarn worked closely with Clear 

Channel to ensure a made-to-measure 

fit for M-Tray on the new bus shelter 

design. Wallbarn says M-Tray is the 

perfect solution for bus stops and other 

transport infrastructure given its fully 

established nature and modularity. All 

elements of a traditional roll-out system 

– drainage, root barrier, substrate 

and sedum or wildflower plants – are 

contained within its 500mm x 500mm 

x 100mm cassettes, each of which are 

mini self-contained, fully grown green 

roofs delivered from field to site within 

24 hours if required, assisting tight 

project schedules and ensuring plants 

arrive in pristine condition. The oneman 

lift trays simply click together, 

delivering a secure, established living 

roof quickly, easily and cleanly with 

virtually no on-site waste. A major 

benefit of the M-Tray system is the 

ability to remove/re-lay individual trays 

if deck access is required. This can be 

done quickly and easily and does not 

disrupt the entire roof. 

Importantly for installation in public 

places, M-Tray has achieved industry 

leading fire classification BRoof (T4) 

EX AP gained through independent 

testing by Warrington Fire carried 

out to CEN/TS1187:2012 (Test 4) and 

CEN/TS 16459:2019, Test methods 

for external fire exposure to roofs. 

The system demonstrated no fire 

penetration. M-Tray is also compliant 

with the GRO Code 2021 and complies 

fully to BS 8616:2019 Specification 

for performance parameters and test 

methods for green roof substrates. 

Julian added: “For the Leicester 

project we supplied M-Tray planted 

with wildflowers grown at our nursery 

in Hampshire. It’s a beautiful blend of 

more than 18 different plants which 

change in appearance according to 

the season, offering all year round 

greening, comprehensive cover and a 

gorgeous carpet of flowers in summer.” 

Will Ramage, Clear Channel’s Managing 

Director, commented: “Our Living 

Roof Product was first introduced in 

the Netherlands and we were excited 

to bring this green technology to the 

streets of the UK. Finding the right 

partner was essential in making this a 

reality, and we look forward to building 

on our partnership with Wallbarn by 

rolling out even more Living Roofs to 

UK streets. We could not be happier to 

be working with such a forward-thinking 

and award-winning company.” 

The new bus stops have been wellreceived, 

as Deputy City Mayor 

Cllr Adam Clarke, who leads on 

environment and transportation, 

explained: “It’s great to see the first of 

Leicester’s new living roof bus shelters 

appearing across the city. We’ve already 

had fantastic feedback from people 


Above and below: Wallbarn’s modular green roof system M-Tray has been installed on 30 new bus stops in Leicester city centre. 

who are as excited as we are to see this 

bee and butterfly, friendly revamp of 

bus shelters taking shape.” 

Contact Wallbarn 

Tel: 020 8916 2222 

www.wallbarn.com 

Tweet: @wallbarn 

Leicester’s initiative is perfectly in step 

with the growing desire worldwide 

to ‘green’ urban areas to help tackle 

climate change, a challenge being 

discussed by world leaders at COP 

26 in Glasgow next month. Wallbarn 

believes that greater emphasis should 

be placed on ‘retro-greening’ towns and 

cities, taking advantage of the hundreds 

of thousands of square metres of 

redundant flat roofs on residential, 

commercial and public buildings. A 

2008 study* found that 19.8 hectares 

of green roofs in Chicago removed 

1,675kg of air pollutants over the course 

of a year, of which 52% was ozone and 

27% nitrogen dioxide, and that’s before 

taking into account reduction in the 

Urban Heat Island effect and rainfall 

attenuation. 

* ‘Quantifying air pollution removal by green roofs in 

Chicago’, Jun Yang, Qian Yu, Peng Gong 


ACADEMIC CORNER 

GREEN INFRASTRUCTURE 

& MENTAL HEALTH 

Dr Tom Young looks over some of the evidence that highlights 

the positive impact green infrastructure and systems have on 

mental health and the overall well-being of individuals. 

The benefits of green space have 

been appreciated for millennia. 

The rise of dense urban spaces 

encouraged the development of green 

pockets within cities, to allow escape 

from hot, busy and noisy areas. 

Although the benefits of green spaces 

in cities have always been recognised, 

it is only in recent years that these 

benefits have begun to be fully 

quantified. This has started to allow 

policy and development strategies to 

place more emphasis on long-term 

human health outcomes of urban 

design. Much more work is needed 

to influence policy and planning 

legislation, but a wealth of knowledge 

and evidence proving the economic, 

human health and environmental 

benefits of incorporating 

green space into cities 

already exists. 

Placed under the banner 

‘green infrastructure’, 

urban green spaces range 

from parks, community 

gardens, green roofs, green 

walls, forests, landscaped areas 

and private gardens. Human health 

benefits are realised in a large number 

of interconnected ways, not all of 

which are immediately obvious. These 

can be broadly spilt into the following 

categories, Provisioning (natural 

resources produced), Regulating 

(maintaining the environment we live 

in) and Cultural (non-material benefits) 

(Coutts & Hahn 2015). I’ll focus on 

Left: Dr Tom Young is on the GRO 

Board and Environment Systems 

Manager at STRI Group. 

Regulating and Cultural 

benefits of green space. 

Regulating 

Air pollution: vegetation can 

absorb and capture air pollution, 

reducing levels in the air for humans 

to ingest. However, care must be 

taken as sometimes certain species 

can contribute to respiratory disease 

though the production of pollen, 

volatile organic compounds or through 

altering air movement (Pawankar et al 

2011, Hewitt et al 2020). 

Continued on page 16 >>> 


STARK TO STUNNING 

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Versatile M-Tray modular green roof system 

Flowering sedum & all-year vegetation. 

Beautiful, natural habitats for urban 

cityscapes. 


0208 916 2222 

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commercial public sector domestic

ACADEMIC CORNER 

>>> Continued from page 14 

Climate regulation: Urban areas 

generally experience more extreme 

ranges in air temperature and flooding 

due to the large amount of hard, 

impermeable surfaces which absorb and 

reemit heat during the night, plus allow 

stormwater to run off extremely quickly. 

These effects are being exacerbated 

with the impact of climate change (Patz 

et al 2005). Elevated city temperatures 

are linked to 1000’s of deaths a year, 

particularly during heat waves. Largescale 

modelling and studies have shown 

that city-wide greening can reduce 

overall city temperatures by up to 

2.2ºC and the physiological equivalent 

temperature (method of assessing 

temperature effect on human body) 

by up to 14ºC (Balany et al 

2020). Green spaces have 

also been used during 

heat waves as ‘cool’ 

islands to allow people 

to go and obtain some 

relief during hot night 

time conditions 

(Aram et al 2019). 

Cultural 

Mental health: A greater 

understanding of the link between 

human physical and mental health 

thankfully now places mental wellbeing 

as just as important as physical 

health (Coutts & Hahn 2015). Human 

relationships with nature is complex 

and hard to summarise concisely as 

individuals do respond differently to 

different environments depending on 

a range of social and physical health 

variables. However, the ability of green 

space to provide ‘mental restoration’ 

to renew “diminished functional 

resources and capabilities” results in a 

clear relationship with stress reduction 

and improved cognitive ability (Hartig 

& Staats 2003, Coutts & Hahn 2015, 

Ulrich et al 1991). 

A classic study from Ulrich in 1984 

showed that patients recovering from 

surgery required shorter hospital 

Left and above: A bit of green amongst the grey. Images courtesy of GRO. 

stays and reduced use 

of painkiller drugs when 

viewing trees from their 

hospital window, as opposed 

to a brick wall (Ulrich 1984). 

Access to or visibility of nature 

has also been shown to significantly 

improve patient and carer experience 

for palliative (end of life) patients. Even 

simple methods such as viewing a bird 

feeder, having an access ramp from a 

care room or, as mentioned earlier, being 

able to view trees from a window can 

have a large positive effect on patient 

stress, psychological well-being of patient 

and satisfaction of family/care givers on 

quality of care (Sagha et al 2018). 

Social 

Physical activity: A large amount of 

literature now exists which shows a 

relationship between access to green 

space and physical activity (Kaczynski & 

Henderson 2007), which can translate 

into reduction in obesity (Lachowycz & 

Jones 2011), although the relationship 

is complex and requires further 

investigation. Additional benefits can be 

16 GREENSCAPE AUTUMN 2021 • www.greenscapemag.co.uk 

realised in the social interactions from 

creating and managing green spaces, 

for example community gardens and 

assets. 

The pool of available data quantifying 

the many interconnected and complex 

ways in which green infrastructure 

can improve human lives is now 

vast. The role of green infrastructure 

professionals is to now use this wealth 

of information to obtain clear and 

concise metrics to justify the use of 

green infrastructure and systems as 

vital parts of urban developments. 

Armed with this type of data, the 

argument against nature and resident 

friendly design becomes diminished, 

with the old way of doing things, in my 

view, much less sensible or attractive. 

Full references available to view at 


Contact 

STRI Group 

Tel: 01274 565131 

www.strigroup.com 

E: tom.young@strigroup.com 

Tweet: @striturf_tomy / 

@striturf

The Water Gardens, London 

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ZinCo Green Roof Systems Ltd. . office@zinco-greenroof.co.uk . T: 01993 229700 . www.zinco-greenroof.co.uk

GREEN TALK MICHELLE WRIGHT 

“NO TWO BUILDINGS ARE THE 

SAME AND NEITHER SHOULD 

THEIR GREEN ROOFS BE” 

We put the questions to Michelle Wright of ICB (Projects) Ltd., 

discussing the uptake of green systems, interesting green roof 

projects the company has been involved with, and what can be 

done to raise the profile of green roofs and associated systems... 

GM: Could you tell us a bit about 

ICB, the company’s offering and 

the types of projects you get 

involved with… 

MW: ICB (Waterproofing) Ltd was 

established over 35 years ago, first 

introducing the German-born alwitra 

single ply membranes to the UK roofing 

market. From the off-set, sustainability 

has been a key focus for ICB, originally 

using the tagline, Sustainable Roofing 

Solutions, due to the environmental 

kudos given to the alwitra membranes 

with their plasticiser-free composition, 

recyclability, root-resistance 

and claiming the industry’s first 

Environmental Product Declarations. 

As the business evolved, more 

waterproofing product ranges were 

introduced, and then in 2008, ICB 

(Projects) Ltd was formed as our 

installation arm. This addition allowed 

us to reinforce our sustainable offering 

to include the design, supply and install 

of ancillary products such as green 

roofs, living walls and solar PV systems. 

Carbon-neutral for over ten years, we 

are proud to conduct business in a 

way which works towards eco-proofing 

the future. Our products are installed 

on projects across all sectors but are 

particularly popular in the Residential, 

Education and Hospitality sectors. 

Our green roof system, EVAGREEN, 

has been developed to meet every 

type of eco-friendly specification, 

from extensive, low-maintenance 

installations, to elaborate intensive 

planting, promoting biodiversity and 

ecology and offering pleasing 

aesthetics whilst affording no 

compromise to the essential 

function of the roof; that is, 

to prevent water entering 

the building. 

With regards to green 

roofing, how is the sector 

performing and do you 

anticipate growth in this area 

considering the Government’s 

climate change targets? 

A surprisingly new trend, modern 

day green roofing was the result of a 

German architectural solution against 

strong winds and rainstorms in the 60s 

& 70s, becoming increasingly popular, 

particularly after interest in green 

architecture surged globally in the late 

nineties. 

In a short space of time, the sector has 

sky-rocketed and is performing well 

with a significant increase in green 

roof area and generated revenue year 

on year, previously demonstrating an 

impressive growth of 17.4% in a single 

year alone. We’ve seen first-hand 

the number of our own green roof 

enquiries accelerate exponentially over 

the past few years. 

Ambitious Government climate change 

targets are pushing urban greening 

to become a fundamental element of 

building design, securing long-term 

future growth of the green roof sector 

as designers 

and architects 

incorporate green 

roofs during the 

early conception 

stages of projects. 

Achieving a 78% reduction in emissions 

by 2035 compared to 1990 levels 

is no easy target, but incorporating 

green roofs into future infrastructure 

as well as the existing refurbishment 

market will help to attain such a goal 

through carbon sequestration and 

natural insulation, whilst also easing 

climate change impacts and socioenvironmental 

issues like flooding, 

poor air quality and biodiversity loss. 

The main challenge will be to reduce 

the number of green roofs which are 

‘value-engineered’ out of projects at 

construction phase. 

With this in mind, what more 

should the Government be doing to 

incentivise green roofs in towns and 

cities throughout the UK? 

The Government plans to meet 

targets by investing in new green 

technologies and innovation and has 

already concluded that the costs of 

action are outweighed by the significant 


Images from left to right: Michelle Wright 

of ICB (Projects) Ltd.; The Nottingham CSC 

Building project that ICB was involved with; 

a green roof project in Wembley. 

benefits. Whilst these investments 

would certainly benefit the future of the 

industry, some kind of stop-gap fund 

would be useful in the shorter term to 

improve the affordability of green roofs 

for both small and large-scale projects. 

Considering 85% of the buildings that 

will be in use in 2050 already exist 

today, investment in the greening of 

refurbishment projects makes much 

more sense, especially when the 

protection provided by a green roof 

can extend the lifespan of the roof by 

an average of 23 years. Biodiversity Net 

Gain policies have now been rolled out 

across several Local Authorities, making 

it more difficult (or expensive) to build 

any new developments without at least 

some green elements. A wider roll 

out of these schemes could fast-track 

climate change achievements. 

We seem to be experiencing more 

severe weather patterns on a more 

regular basis now – is the message 

around the role that green / blue 

roofs can play in reducing the impact 

of severe rainfall getting through to 

building owners and developers? 

– the 

message 

about green 

and blue roofs is still not wide-spread 

enough, although interest through 

necessity is certainly increasing with UK 

costs estimated to rise to £619 million 

at a 4° rise in temperatures. Using 

natural systems to rectify man-made 

problems is the way forward and we are 

writing more blue roof specifications 

than ever before. The technology/ 

offerings are developing quickly to 

tackle a variety of design constraints. 

Blue roofs utilising SuDS can now retain 

60 to 72% of rainwater runoff! Through 

our CPD seminars, we’re teaching as 

many designers as possible about 

the impressive performance of blue 

roofs, hoping that the message will get 

through to the building owners and 

developers of tomorrow. 

How important is it to keep raising 

the profile of green roofs, as well 

as focusing on the importance of 

best practice when it comes design, 

specification and installation? 

It is more important than ever to raise 

the profile of green roofs. With the UK 

(London) ranking eighth in the world 

for green roofs by density, we have the 

potential to become Global leaders in 

green infrastructure, whilst at the same 

time reducing climate change impacts, 

increasing biodiversity and improving 

health and well-being for ourselves 

and future generations. 

Green roofs are being 

installed thick and fast, 

but sadly there are 

so many cases of 

incorrect design, 

wrong specification, 

shoddy installation 

and a frequent 

disregard for crucial 

aspects of a successful 

installation like irrigation 

and maintenance. 

Organisations like GRO 

are helping to focus on the 

importance of best practice and 

bringing standards in line across the 

board. Embedding their practices will 

result in confidence in successful, 

durable, timeless green roofs. 

Is there a danger that building 

owners and other specifiers 

aren’t aware of the various 

options available and important 

differentiations when specifying 

a green roof? – Is there enough 

awareness that a green roof is not a 

‘one size fits all’ solution? 

There’s so much to consider when 

specifying a green roof, from the 

position of the building and orientation 

of the roof to the weight limitations 

and levels of maintenance required. No 

two buildings are the same and neither 

should their green roofs be. This isn’t 

an easy message to get across and 

unfortunately, these differentiations 

Despite these severe weather patterns – 

which cost the UK £340 million annually Continued on page 20 >>> 


GREEN TALK MICHELLE WRIGHT 


are only considered once the green 

roof has failed, all too often after a very 

short life. 

What are some of the more common 

mistakes designers and installers 

make when it comes to green roof 

projects? 

We’ve come across a lot of green roof 

projects where there has been zero 

thought to the need for irrigation or 

maintenance. Even the most basic 

sedum roof should, at some point, be 

offered some form of irrigation and 

maintenance to perform at its absolute 

best and stay looking healthy. Without 

this consideration, dependant on the 

climate and plant variation, a green roof 

can die off very quickly, becoming a 

waste ground and limiting the ecology 

which could have flourished. We 

recommend irrigation and maintenance 

for all of our green roofs and offer 

packages to cover these. 

Another common mistake is not 

factoring in a suitable retention system 

when designing a green roof to a pitch. 

Without an adequate retention system, 

the build-up will not stay in place for 

very long at all. We select these systems 

on a project-specific basis to ensure 

that our green roofs stay in place no 

matter the pitch. 

retention system design as well as 

roof access & safety and logistical 

implications. 

If there was one roof that you could 

green anywhere in the UK, which one 

would it be? 

Imagine the Palace of Westminster 

with a green roof! It would be a huge 

statement and really show that the 

Government are serious about the 

environment. The Google Maps satellite 

view would look great! 

Can you tell us about a green roof 

project you’re particularly proud to 

have been involved with… 

The Nottingham CSC building was such 

a great project to be involved with. The 

sustainable alwitra single ply membrane 

and EVAGREEN green roof system 

helped the award-winning building 

at Nottingham University to achieve 

BREEAM Outstanding status and was 

a first of its kind as the only carbonneutral 

laboratory in the UK. 

Construction relies far more on technology 

and communication than you would 

believe. Whilst most business carried on 

almost as usual on site, these functions 

are just the tip of the iceberg. Moving 

all pre-build operations – specification 

meetings, CPDs, research material – into 

a remote, online environment was a 

testing experience, but in some aspects, 

it worked better than before and we 

managed to reach a record number of 

specifiers in this manner. 

Are there reasons to be positive 

within the green roof sector and the 

wider construction industry going 

forward? 

The green roof sector is a shrine of 

positivity in its own right. Every green 

roof brings us one step forward in 

the right direction towards reducing 

the impacts of climate change and 

balancing out the negative effects 

which have been created through 

the urbanisation of Britain. Future 

Government investment into urban 

greening and changing attitudes 

towards health and wellbeing following 

the pandemic should see continual 

growth for the green roof sector. 

What can we expect from ICB going 

forward? Any new developments to 

look out for? 

What are some of the myths that 

exist around green roofs? Is there 

one that particularly annoys you? 

There are all sorts of myths around 

green roofs. Some say they are 

expensive – without factoring in the 

financial, ecological and social rewards 

– and others believe that they leak, 

forgetting that there is a full, rootresistant 

waterproofing layer beneath 

when done properly. 

A particularly foolish myth is that 

anyone can install a green roof. There 

is so much going on behind the scenes 

when it comes to green roofs including 

calculations for loadings, species 

selection, component assembly and 

If you had one piece of advice about 

working and progressing within the 

construction sector, what would it be? 

Keep learning. Technology is moving 

so quickly and practices, software and 

consumer behaviours are constantly 

changing. Following the key industry 

bodies such as the NFRC, SPRA, LRWA 

and GRO can help with staying one step 

ahead. 

What have you learned about your 

role and construction in general 

over the last year-and-a-half whilst 

operating during the pandemic? Are 

there lessons you’ll take forward 

with you? 

20 GREENSCAPE AUTUMN 2021 • www.greenscapemag.co.uk 

We are constantly looking to improve 

and provide the best technical advice 

and products for the job. We continue to 

push specifiers and customers to move 

into more biodiverse solutions and even 

to work with us on creating Bio-Solar PV 

Roofs where the two ‘green’ solutions 

can complement each other and help 

our environment even further. 

Read the full interview at 


Contact 

ICB (Projects) Ltd. 

www.icbprojects.co.uk 

Tel: 01202 785200 

Tweet: @ICB_Projects

Green, Brown & Blue Roof Systems / Solar PV / Tesla Powerwall / Roofline / Roof Safety 

WE CREATE 

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We offer a complete solution including 

surveys, calculations, design & technical 

(CAD) support, supply & installation - all 

backed up by industry leading guarantees 

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Contact us for technical advice or a quote. 

Discover more at icbprojects.co.uk 

01202 785200 info@icbprojects.co.uk www.icbprojects.co.uk 

UK Head Office Unit 9-11 Fleets Industrial Estate, Willis Way, Poole, Dorset BH15 3SU

BLUE ROOFS MYTHBUSTERS 

MYTH: BLUE ROOFS STORE 

WATER PERMANENTLY! 

Anthony Barnett of ABG Ltd. looks at the considerations 

involved when specifying Blue Roofs, dispelling the myths 

around the structural loading implications and ‘storm water 

storage’ function of Blue Roof systems. 

When it comes to the range of 

Sustainable Drainage System 

(SuDS) techniques available 

to local authority planners and property 

developers, Blue Roof systems tend to 

be the least well known, partly owing to 

them being a relatively new concept. 

The term ‘Blue Roof’ can also be 

misconstrued as meaning a roof 

top swimming pool or storage tank. 

Architects, structural engineers and 

waterproofing companies are rightly 

averse to permanently storing large 

volumes of water on a roof from both a 

structural and waterproofing integrity 

point of view, so now is a good time to 

bust these particular myths! 

Rather than being thought of as storm 

water storage, Blue Roofs are only 

designed to provide temporary storm 

water attenuation. For around 95% of 

the time the roof drains as normal via 

the rainwater outlets and it is only in the 

event of heavy and prolonged rainfall 

that the Blue Roof system begins to 

restrict the discharge rate of rainwater. 

A typical system design will see the Blue 

Roof’s attenuation voids begin to fill up 

as rainfall intensifies, before it drains 

to empty over a 12 hour period. In this 

way, water does not cascade rapidly 

from rainwater outlets and overburden 

the local storm water drains, sewer and 

river networks. 

Designs are typically calculated to 

model the drainage of the roof to 

match a 1 in 100 year storm event, plus 

a 40% allowance for the effects of 

climate change. Geographical location 

and orientation are an important part 

of the calculation and the average 

amount of rainfall in that location 

and the prevalent wind direction are 

considered. In the UK, values are taken 

from either the flood studies report 

(FSR) or flood estimation handbook 

(FEH 2013), depending on which is most 

relevant to determining the exact storm 

design. 

Key to controlling the discharge rate 

from the roof is the restrictor chamber 

and these are positioned above 

rainwater outlets to restrict the flow 

rate of storm water. As the void formers 

fill, the chambers have a series of inlet 

positions that slow the volume of water 

entering the drain. The chambers 

include a geotextile filter to prevent 

leaves and debris from blocking the 

outlets, whilst also providing a filtration 

function. 

Installing a Blue Roof system has a 

positive impact on the quality of the 

water discharged as a result, and before 

the water reaches the roof outlet, it has 

passed through several filtration layers 

to remove particulates and pollutants. 

Even if the surface finish isn’t green, the 

water has passed through at least two 

layers of filtration, with water treated to 

such a degree that it reaches the level 

required in treatment train stage one 

of the SuDS process, allowing it to be 

released from the roof directly into the 

river or sewer systems. 

The introduction of a Blue Roof 

doesn’t usually, but may have loading 

implications for the structure of the 

building, and a structural engineer 

should be consulted at an early stage 


Inset, left: Restrictor 

chamber showing 

height adjustable 

drainage inlets and 

geotextile filter. 

to determine any 

constraints. 

These are often 

not as onerous 

as might be 

expected, 

however, 

since the 

Blue Roof 

attenuates 

collected water 

across the 

entire area of the 

roof at a shallow 

depth, typically less 

than 100mm. At full 

capacity this would only 

exert a maximum additional load 

of 1.0kN/m 2 . Components are available 

and designed to cover nearly all loading 

eventualities including; landscaped 

areas, podium decks for emergency fire 

and HGV vehicle access and large HVAC 

plant and Solar PV installations. 

I hope this brief article helps to 

introduce some of the considerations 

involved when specifying a Blue 

Roof system and clears up the myths 

regarding the concept of storm water 

storage and the structural loading 

implications! 

Contact ABG Ltd. 

T: 01484 852096 

www.abg-geosynthetics.com 

Tweet: @ABG_ltd 

More on Blue Roofs, page 34. 

Left: Attenuation void 

formers being installed at 

the new St James Quarter 

retail development in 

Edinburgh 


GREEN ROOF POLICY 

“NOW IS THE PERFECT TIME TO TALK TO 

PLANNERS ABOUT GREEN ROOFING!” 

Paul Collins is a member of GRO and planning and development surveyor who works for 

Nottingham Trent University. Below he explains why he feels new Design Codes and a new 

Environment Act should be a policy and legal marriage for more green roofs… 

In some countries, the provision of 

green roofs are mandated by law. 

By contrast the planning systems of 

the four UK nations are fundamentally 

discretional in nature and based on 

‘policy’. Therefore, it is important for 

green roof professionals to understand 

the planning tools that influence 

the uptake of green roofs in order 

to engage positively with relevant 

authorities and promote the industry 

successfully. 

In the UK, local authorities include 

reference to their expectations in local 

plans. Since 2008, The Greater London 

Authority has had a number of key 

policy clauses in its regional plan, which 

the individual boroughs have then taken 

as a starting point for their own local 

plans. Outside London, Sheffield has 

been one of the most enthusiastic early 

adopters of strong green roof policies. 

If developers want to get planning 

permission in that city, they know there 

is a clear expectation that they will have 

to include them. 

More recently, many other local 

authorities have adopted planning 

policies to support green infrastructure 

strategies more generally, including 

green roofs. Runnymede Borough 

Council, for example, have produced a 

new consultation draft ‘Supplementary 

Planning Document’ (SPD) called 

‘Green and Blue Infrastructure’ (GBI). 

SPDs are produced to support a local 

plan on a particular detailed policy 

issue. A section of this SPD states: “as 

a key component of the GBI network, 

particularly in urban areas with a 

constrained land supply and competing 

land uses, green roofs and living walls 

Above: Sharrow School Sheffield: “Sheffield has been one of the most enthusiastic early 

adopters of strong green roof policies” . Overleaf: Alliums flowering on Sharrow School roof. 

can be used on existing buildings or 

new development.” 

The SPD also provides a web link to 

the excellent report “Living Roofs and 

Walls from policy to practice: 10 years of 

urban greening in London and beyond” 

written by Dusty Gedge and Gary Grant. 

A new opportunity is now emerging to 

further embed the support for green 

roofs in local planning policy via new 

proposed changes at national level. 

The Ministry for Housing, Communities 

and Local Government (for England) 

– MHCLG – followed up its previous 

National Design Code Documents by 

publishing consultation outcomes 

on 20th July this year. This guidance 

provides ‘clear design parameters’ to 

help local authorities and communities 

decide what good design looks like for 

their area, and can provide a framework 

for healthier, greener and more 

distinctive places with consistent high 

quality of design. 

One of the ten design quality factors 

is ‘nature’ and the simple proposition 

that nature and green spaces should 

be woven into the fabric of our villages, 

towns and cities. This will provide 

benefits in terms of health and wellbeing, 

biodiversity, climate change 

resilience and flood mitigation. This 

national code references green roofs 

as part of the package of potential 

supporting measures. 

In practical terms, if a Design Code for an 

area is adopted, it will act first as a guide 

for developers to have regard to in the 

design and specification of new buildings 

– and second as a decision-making tool 

in the granting of planning permission. 



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GREEN ROOF POLICY 


Design Codes can be produced 

for: 

1. The whole local authority area 

including all existing settlements and 

development sites. 

2. Selected parts of existing settlements 

and development sites. 

3. Just development sites. 

In some senses the Design Codes will 

be similar in effect to SPDs, but the 

focus of Design Codes are on ‘design’, 

whereas an SPD could be on affordable 

housing, telecommunications or 

developer financial contributions. 

The challenge now is for green roof 

professionals and the industry to 

further promote and explain the 

benefits of green roofs to local 

authorities and their communities, and 

ensure they are explicitly embedded 

in local design codes. In doing so, the 

importance of specifying technical 

best practice should be at the heart 

of that campaign and the Green Roof 

Organisation (GRO) can help in that 

regard. The bibliography on ‘nature’ 

in the appendix to the Government’s 

National Model Design Code currently 

doesn’t make reference to ‘The GRO 

Green Roof Code.’ One of our first tasks 

is to get it included in the next updated 

edition. 

Alongside the introduction of Design 

Codes is the proposed Environment Act. 

This will impose a legal requirement 

that all new developments will put back 

more nature/biodiversity than was 

there originally, which is referred to as 

Biodiversity Net Gain. Whilst there are 

some issues still to be resolved with 

metrics to be adopted in supporting 

habitat rich biodiversity, it is a good step 

forward. 

This is the opportunity: if a Design Code 

makes reference to the expectation of 

green roofs on developments within 

a designated area, and there is also 

a new legal commitment to increase 

biodiversity on site by at least 10%, 

then green roofs offer a brilliant way to 

achieve this goal. 

To conclude: how to move forward 

GRO is committed to promoting the 

green roof industry in ways which 

will genuinely benefit communities 

and the environment. To this end, 

we will actively encourage the 

inclusion of the GRO Code of Best 

Practice in Government Design 

Code documentation, and support 

our members and any industry 

professionals in engaging with their 

local authorities when and where 

design codes are produced. Strong 

green roof planning policies are a crucial 

step towards the industry’s growth and a 

greener future – so now is the perfect time 

to talk to planners about green roofing! 

References available on request, or 

view at www.greenscapemag.co.uk 

Contact GRO 

email: 

membership@ 

greenrooforganisation.org 

www.greenrooforganisation.org 

Tweet: @RoofGro

PROJECT FOCUS SAXON COURT 

INSTALL, GROW, RELOCATE: 

THE GREEN ROOF PROJECT 

ON THE MOVE 

We take a look at an interesting project in Milton Keynes which 

showcases the benefits of green roofs in urban environments, plus 

hear how those involved are looking to the future by involving and 

training young people from YMCA MK on the project. 

Two projects, one green roof; 

that’s the aim of a groundbreaking 

initiative to revamp a 

YMCA with a living roof removed from a 

development 1km away. 

Saxon Court in Milton Keynes has 

undergone a temporary transformation 

into a ‘live lab’, showcasing multiple 

green, blue and biosolar roof 

applications together with a roof top 

vegetable growing project, all installed 

while planning permission is gained to 

redevelop the site. 

Green infrastructure and living roof 

specialist Bridgman & Bridgman is 

spearheading the venture – entitled 

The Green Roof Project – with support 

from Milton Keynes Council, aiming 

to demonstrate the many benefits 

of green roofs in towns and cities for 

biodiversity, carbon capture and fruit/ 

vegetable production. 

An integral part of the plan is to also 

train young people from YMCA MK to 

install the living roof and support them 

in gaining the necessary expertise and 

certification in the installation and 

maintenance of green roofs. When the 

Saxon Court scheme is concluded, the 

newly skilled operatives will repurpose 

materials from its roof top to top off the 

town’s new YMCA building. 

Award-winning green roof manufacturer 

Wallbarn, along with other GRO 

members, is supporting the project 

by supplying its modular M-Tray green 

roof system, which suits the scheme 

perfectly due to its pre-fabricated, easy 

to install – and remove – nature, as 

Director Julian Thurbin explained: “If 

there was a project perfect for M-Tray it 

would be Saxon Court/YMCA MK simply 

because of the system’s pre-fabricated, 

modular characteristics. All elements 

of a traditional green roof – drainage, 

root barrier, substrate and sedum or 

wildflower plants – are contained within 

its polypropylene trays. The plants are 

fully established and the system quick 

to install, delivering an instant green 

roof with little fuss. 

“It’s also as quick and easy to take up as 

to put down, which for our customers 

gives peace of mind should roof decks 

require attention. However, for this 

project it makes the roof transfer 

between Saxon Court and YMCA MK 

really straightforward – just lift the 

trays and transport them the 1km or so 

between buildings. 

“We do believe this is a first for M-Tray 

and are delighted to be involved with 

the project. We have enormous respect 

for Chris Bridgman (of Bridgman and 

Bridgman) and have admired the 

work he has done in training the next 

generation of landscaping and green 

roof professionals and in safety and 

standards in the green roof sector. He 

is a standard bearer for the industry. 

It is also a marvellous opportunity to 

showcase the different types of green 

roof design and systems and is available 

for us to show to architects, designers, 

local authorities and other developers/ 


clients to demonstrate the scope of 

green roofs to help them in selecting 

the best type of green roof for their 

schemes. It is doing fantastic work in 

raising awareness of the benefits of 

green roofs, their suitability for retrofit 

and – really importantly – training 

young people to be installers of the 

future,” added Julian. 

Chris Bridgman said as well as 

teaching skills and creating job 

opportunities, the project aimed 

to encourage local authorities, 

schools, property owners, facility 

and building managers and 

homeowners to consider 

greening rooftops to help the 

fight against global warming 

and the rapid decline of 

biodiversity. 

He said: “We really 

appreciate the support of 

Wallbarn in creating this 

opportunity to demonstrate 

the beneficial role of urban 

green infrastructure in the fight 

against climate change and bring 

new people into the industry. The 

M-Tray system is ideal for retrofitting 

rooftops such as Saxon Court. This is 

a very clean and affordable method of 

retrofitting green infrastructure.” 

Contact 

Wallbarn: 


Tel: 020 8916 2222 

Tweet: @wallbarn 

The Green Roof Project supports 

work taking place in response to the 

Milton Keynes Green Roof Report 2019, 

which identified the green roof retrofit 

potential in central Milton Keynes and 

aligns with the council’s Sustainability 

Strategy. Milton Keynes aims to be 

carbon neutral by 2030 and carbon 

negative by 2050. 

Images: Wallbarn’s M-Tray has been utilised 

on The Green Roof Project at Saxon Court in 

Milton Keynes, which is headed-up by Chris 

Bridgman of Bridgman & Bridgman with 

support from Milton Keynes Council and 

other GRO members. The project showcases 

the many benefits of green roofs in towns 

and cities plus is training young people from 

YMCA MK in the installation of green roof 

systems. 


GREEN ROOF COMMENT 

GREEN ROOFS: NO SUCH 

THING AS NO MAINTENANCE 

By Nick Day, Managing Director of Optigrun. 

Contact Optigrun 

www.optigruen.co.uk 

Tel: 0203 589 9400 

Tweet: @OptigreenLtd 

A 

green roof has been installed 

on the building you have 

bought or leased. Now you 

just leave it to do its own thing and 

it won’t need maintaining…right? 

Wrong! Unfortunately, too often this is 

the fate facing a green roof and as a 

consequence many are not performing 

or looking as they should. The reality, 

however, is that all that is actually 

required are regular and occasional 

maintenance visits. 

We’re mainly talking here about 

extensive green roofs with sedum or 

wildflower vegetation. All of these roofs 

have a relatively shallow build-up with 

a typical growing medium depth of 

around 80-150mm and are often not 

regularly seen. Intensive roofs are likely 

to be highly visible being either on a 

podium deck or an accessible roof, and 

it becomes fairly obvious if they haven’t 

been maintained. They will also require 

a much higher number of maintenance 

visits in any one year. 

The path to a well-maintained green 

roof should start when the building 

is being designed. The provision 

of permanent safe access and fall 

protection is vital to ensure that the 

maintenance operative can carry out 

works safely and without, ideally, there 

being the need to spend a lot of time 

organising external facilities every 

time a visit is due with, consequently, 

considerable expense to the owner or 

occupier of the building. 

Another key feature to factor in is a 

water supply close to the green roof 

area. Although permanent irrigation 

may not be a requirement of the 

specification, the roof will at least 

A trained operative carrying out 

maintenance on a green roof. 

need a temporary facility whilst it is 

becoming established. There may also 

be a need to water the roof during 

dry spells or droughts, particularly if 

temperatures during heatwaves rise in 

the future, even for sedum plants. 

Once the project reaches contract 

stage it’s important to establish who is 

responsible for the care of the green 

roof between installation and practical 

completion, and handover of the 

building. There may be a considerable 

amount of time that elapses between 

these events and it’s important for 

responsibilities to be clear earlier in 

the contract. Many a green roof has 

suffered badly during this phase. 

How often does a green roof 

require maintenance? 

For an extensive roof, once established, 

twice annually should be sufficient. Be 

aware, however, that roofs with dry 

seeding or plug planting may need 

more weeding during the early years of 

their life until vegetation cover reaches 

an optimum level. For intensive roofs, 

the frequency of visits will depend on 

the type of planting involved. 

For extensive roofs the maintenance 

tasks are: 

• Removal of unwanted weed and grass 

growth, tree saplings and other woody 

plants from the roof area. 

• Make sure that pebble margins 

are kept clear of vegetation. This is 

important as these margins are a fire 

safety feature. 

• For roofs with wildflower vegetation, 

it’s important once seed heads have 

dropped that spent foliage is cut back 

every autumn and the arisings removed 

from the roof. 

• Ensure that rainwater outlets, gutters, 

and inspection chambers are clear of 

debris and clean out as necessary. 

• Apply a purpose-made slow release 

fertiliser once a year. 

In addition to the above, localised 

areas of sparse vegetation or even 

bare patches may appear every few 

years. This is quite common and can 

be rectified by supplementary planting. 

In the case of sedum roofs, plants 

removed from the pebble areas during 

maintenance visits can be relocated 

to fill in gaps in the vegetation. 

Alternatively, additional plug plants can 

be installed, or dry seeding carried out 

depending on the requirements of the 

individual roof. 

Who should carry out this work? 

Ideally it should be left to an 

experienced specialist contractor with 

a full understanding of green roofs and 

their requirements, as well as the health 

and safety implications of working at 

height. The good news is that costs 

for maintenance visits are relatively 

modest. 


Specify insulation 

that stands the 

test of time… 

Creating tomorrow’s green 

roofs, today. 

Save time and future costs by specifying ROCKWOOL stone 

wool insulation, which has shown to retain its insulation 

characteristics and properties for more than 55 years after 

initial installation. 

Stone wool insulation delivers key benefits for green roofs: 

Durability 

Stone wool insulation is dimensionally stable and its 

performance won’t deteriorate over a building’s lifetime. 

Fire safety 

Stone wool insulation can withstand temperatures 

in excess of 1,000ºC and will not burn, helping to 

mitigate the possible fire risks of dried-out vegetation. 

Thermal properties 

Stone wool offers exceptional thermal performance, 

contributing to energy efficiency targets and enhancing 

indoor comfort. 

Acoustic performance 

Trapping sound waves, ROCKWOOL stone wool 

insulation helps to dampen excess noise. 

For a total insulation solution which guards against deterioration 

and futureproofs for tightening fire safety and energy efficiency 

requirements, choose ROCKWOOL stone wool. 

To learn more, 

visit the new 

ROCKWOOL 

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Hub today: 

rockwool.com/uk/ 

flat-roof-hub/ 

www.rockwool.com/uk

GREEN ROOF PROJECT 

RAISING THE ROOF 

Green-tech played a key role in a challenging rooftop garden 

project at the Maggie’s Centre in Leeds... 

Green-tech supplied the 

landscaping materials for the 

rooftop garden of the Maggie’s 

Centre Cancer Charity, which is situated 

in the grounds of St. James’s University 

Hospital in Leeds. 

The charity’s 26th UK centre was 

designed by award-winning landscape 

designers Balston Aguis. It was inspired 

by Yorkshire woodlands and features 

native English species of plants, 

alongside areas of evergreen, to provide 

warmth in the winter months. 

BALI-registered contractor Swinburne 

Horticultural Services Ltd undertook 

the roof garden build and all the 

landscaping works. 

A well-established family-run business 

with over 30 years’ experience installing 

and maintaining landscapes, Greentech 

has worked with Swinburne for 

many years supplying their projects 

across England and Scotland. The 

outside space at Maggie’s Leeds is as 

important as the inside. Inspired by 

founder Maggie Keswick Jencks’ love 

of gardening, Maggie’s Centres work 

closely with the architect and interior 

and landscape designers from the very 

beginning of each project to make sure 

there is a strong connection between 

the outside and inside space. They ask 

their landscape architects to use plants 

that will add colour, scent and interest 

throughout the year. 

Leeds Maggie’s Centre is roofed by three 

overlapping gardens which step down 

and overhang to shelter communal areas. 

The challenge was to span and enclose 

the level changes and reinstate the site’s 

greenery. In this way, the hospital does 

not lose its last green space – it is lifted, 

filled with woodland plants and made 

more accessible and inviting. 

Swinburne Horticultural Services 

installed the roof garden and created the 

landscape vision over several months. 

During this time, Green-tech supplied 

270m 3 of Green-tree Roof garden 

intensive substrate which equates to 

150 dumpy bags and gt Roof Drain 

which provides a lightweight continuous 

drainage layer across the roof structure. 

It collects and stores water to irrigate the 

plants during low rainfall periods 

300 tonnes Green-tree 12mm premium 

Above & below: The outside space at the 

Maggie’s Centre in Leeds is said to be as 

important as the inside. 

topsoil was supplied for the general 

landscaping areas, along with 44 tree 

anchoring kits, Mona irrigation pipes, 

compost and bark mulch. 

In total, 23,000 bulbs and 17,000 plants 

were planted which all help to provide 

a tranquil environment; a calming 

space for all to take time out and 

enjoy the nature around them. Visitors 

are encouraged to participate in the 

ongoing care of these. 

Brian Watson, Landscape Architect 

from Swinburne Horticultural Services 

Ltd, commented: “We worked closely 

with Green-tech as we had to work 

around challenging delivery restrictions. 

Being in a city centre and the hospital’s 

own restrictions meant it was 

imperative that Green-tech made each 

delivery to a very specific and tight 

timescale, which they did successfully. 

They used Moffett equipped artic 

trailers for easier unloading. The 

rooftop garden looks amazing and has 

been well received. I would happily 

recommend Green-tech.” 

Contact Green-tech 

Tel: 01423 332100 

www.green-tech.co.uk 

Tweet: @Greentechltd 


Sustainable 

soils, growing 

media and turf 

Download 

a copy of our 

Guide to Good 

Soils today 

British Standard Topsoil 

Light in texture with good water holding 

capacity. Ideal for environmentally 

conscious landscaping and 

construction projects. 

British Standard Subsoil 

A high quality, clean and consistent 

soil with full traceability. Ideal for 

general infill, raising levels and 

creating landscape contours. 

Roof Garden Substrate 

Intensive and Extensive options 

ensuring healthy plant establishment 

for rooftop or containerised 

planting projects. 

Amenity Tree Soil 

Load bearing, fertile planting medium. 

Enables tree root infrastructure to 

develop under hard urban landscapes. 

ArborRaft Soil 

Works as a rootzone with the 

ArborRaft Tree Planting System. 

Bespoke Mixes 

Rootzones, low fertility soils, subsoil, 

sports soils and structural soils. 

Turfs 

A comprehensive range including 

Wildflower Turf, which provides 

an instant wildflower meadow 

T: 01423 332 100 

E: sales@green-tree.co.uk 

www.green-tree.co.uk 

Green-tree is a trading style of Green-tech Ltd 

Proud to be a 

Supplier Member of:

BLUE ROOFS KEY GUIDANCE 

SPECIFICATION CONSIDERATIONS FOR BLUE 

ROOF SUDS ATTENUATION SYSTEMS 

By Anthony Barnett, Technical Marketing Manager at ABG Geosynthetics. 

Met Office climate projections 

indicate significant 

temperature rises in the 

decades ahead, with extreme weather 

and flooding events becoming more 

frequent. Summer rain is forecast to 

become more intense, leading to a 

greater risk of flash flooding and the 

trend for wetter winters is also likely to 

continue, placing greater pressure on 

existing sewers and flood defences. 

As a result, good water management 

and SuDS (Sustainable Drainage 

Systems) design practices within new 

or refurbishment developments are 

increasingly critical, with traditional 

rainwater drainage systems that 

discharge water from buildings as 

quickly as possible no longer desirable. 

Implementing a blue roof provides an 

important technique to meet SuDS 

planning application conditions, based 

on their contribution to reducing the 

risk of flooding and pollution, 

and their positive impact 

on the local landscape 

and wildlife ecosystems, 

especially when 

combined with a green 

roof or biodiverse finish. 

System configuration 

Blue roofs introduce drainage voids 

and restrictor chambers/orifices 

within the roof build-up to attenuate 

and release water at a maximum 

controlled rate. Under normal rainfall 

events (i.e. most of the year) the roof 

will continually drain like a normal 

flat roof. The blue roof storm water 

management system only comes into 

effect during a heavy downpour / 

key design storm event. At this point, 

the blue roof will slow the rainwater 

discharge to the agreed maximum 

rate to help meet the site’s drainage 

strategy. 

Left: Anthony Barnett, Technical 

Marketing Manager at ABG 

Geosynthetics. 

Local rainfall / flood 

data 

As part of the SuDS design 

process for new planning 

applications, local flood 

report data is analysed to model 

and calculate the attenuation capacity 

required for the roof during storm 

events. The rainfall for the specific site is 

calculated according to location, storm 

duration and return period (the number 

of times in a set period that a storm of 

that magnitude is likely to occur; 1 in 

30 years and 1 in 100 years storms are 

usually considered). In the UK, values 

are taken from either the Flood Studies 

Report (FSR) or Flood Estimation 

Handbook (FEH) data, with an allowance 

made for the impact of future climatic 

change, typically +40%. 

Structural and loading 

considerations 

Above: Close-up of a Blue roof build-up showing geotextile filters, void formers and stainless 

steel restrictor chamber. 

Early consultation with the project’s 

structural engineer should be 

undertaken to consider any additional 

loading constraints, although since 

blue roofs attenuate rainwater across 

the entire area of the roof at a shallow 

depth, typically less than 100mm, this 

only exerts a maximum additional 

load of 1.0kN/m 2 at full capacity. This 

can also be offset against the roof’s 

traditional snow loading. The blue roof 

components can also be designed to 

accommodate nearly all eventualities 

/ final area use, including; landscaped 

amenity areas, podium decks for 

emergency fire and HGV vehicles, and 

large HVAC plant or PV installations. 


Contact 

ABG Geosynthetics: 

www.abgltd.com/products/ 

blueroof.html 

Tweet: @ABG_ltd 

Water quality 

Installing the blue roof system has a 

positive impact on the quality of the 

water discharged. Before the water 

reaches the roof outlet, it passes 

through several filtration layers that 

remove particulates and pollutants. 

Even if the surface finish isn’t green, the 

water passes through at least two layers 

of geotextile filtration. The water is 

treated to such a degree that it usually 

reaches the level required in treatment 

train stage one of the SuDS process, 

allowing water to be released from the 

roof directly into the river or sewer 

systems. 

Waterproofing 

The waterproofing membrane / system 

selection depends on the type of roof 

construction, but a BBA certified system 

(or similar), accredited for use to zero 

falls is recommended. ABG’s blue roof 

system is compatible with both warm 

and inverted roof constructions, and uninsulated 

podium constructions. As with 

traditional roof types, the waterproofing 

should be detailed to standard height 

above the final floor levels, with the 

recommended test methods adhered 

to ensure integrity, and a full structural 

deflection analysis. 

Above: Composite decking surface finish 

for amenity area; Top: Extensive green roof 

finish for promoting new ecosystems. 

Installation process, access and 

maintenance 

Blue roof systems should be fitted as 

part of an approved installer process 

and supervised by the manufacturer’s 

installation team, with post installation 

quality checks and sign off procedures. 

The system must also have a provision 

for regular maintenance and therefore 

future access should be considered to 

suit the final finish, as with all roofing 

applications. Decking areas, paved 

podium decks and ballasted 

roofs are relatively low 

maintenance, whereas 

green roofs usually require 

twice yearly maintenance 

visits to monitor and 

remove invasive species 

and trim vegetation. 

Thermal performance 

Currently the components of a blue or 

green roof are not considered as part 

of the roof build up when calculating 

thermal performance, so the insulation 

design and specification is the same 

as for a traditional roof design. Despite 

the UK building regulations currently 

making no allowance for a blue or 

green roof, research shows that the 

introduction of layers of drainage, 

growing media and vegetation do 

have a positive impact on the thermal 

performance of a roof, with the most 

significant benefit a reduction in solar 

gain. 

Summary 

Blue roofs are rated as one of the 

most sustainable, ‘at source’ SuDS 

techniques and can often meet all 

four of the objectives for good SuDS 

design. When implemented correctly 

they form an integral source control 

and attenuation element for 

modern developments. 

Left: Blue roofs address the 

‘four pillars’/objectives of 

good SuDS design. 


PROJECT FOCUS 

“I THINK THIS COULD BE THE FUTURE OF 

SUSTAINABLE RURAL ARCHITECTURE” 

Ravatherm XPS X ULTRA 300 SL insulation has been specified for Howgate Close, a new ecofriendly 

housing project located at the western gateway to the Nottinghamshire village of 

Eakring, where the site’s 10 acres have been taken out of agriculture production to provide nine 

earth-sheltered homes within a managed wildlife area. 

The future of architecture? A bold 

statement perhaps, but with 

the climate crisis looming ever 

larger, the industry needs to consider 

new ways forward. 

Sustainable housing isn’t a new idea. 

Back in 1975, Professors Brenda 

and Robert Vale published “The 

Autonomous House” – a revolutionary 

book detailing a theoretical house that 

was completely self-sufficient in terms 

of heating, power, water and waste 

treatment. In 1993, they turned their 

ideas into reality and built their own 

home, “The New Autonomous House” 

in Southwell, Nottinghamshire. The 

Vales’ builder Nick Martin subsequently 

commissioned the Vales to design the 

Hockerton Housing Project, a selfsufficient 

earth-sheltered community. 

Against the odds, the group achieved 

planning permission in the open 

countryside for a self-sustaining 

development comprising five fully 

sustainable homes in Nottinghamshire, 

completed in 1998. Alongside 

composting toilets and solar panels, 

the Hockerton houses are unusually 

covered in 500 tons of earth – a 

remarkable feature allowing for minimal 

visual impact, insulating properties, and 

habitat creation. 

And now, a new project is set to make 

history and pave the way for the future. 

From the outside, the houses don’t look 

drastically quirky or out of place. Large 

timber windows in a white rendered 

wall are the only visible face, with the 

other three covered by an earth bank. 

So what really makes these houses 

stand out? Designed with the help of 

the original Hockerton project team, 

Howgate Close is set to provide nine 

highly efficient rented properties for 

local residents at risk of being forced 

out by rising house prices. Under these 

circumstances, the challenge is to 

provide truly affordable homes whilst 

maintaining excellent specifications – a 

problem that has been overcome in 

part by Norfolk-based XPS insulation 

manufacturer, Ravago Building 

Solutions UK. 

Adam Hilmi, Account Manager at 

Ravago Building Solutions, said: “With 

its prestigious new BBA certification, 

we’re proud that Ravatherm XPS X 

ULTRA 300 SL has been specified for 

Howgate Close, and with three and a 

half truckloads (250m 3 ) of product 

delivered to the site in July, the project 

is well underway. ULTRA 300 SL 

has enabled a radical negotiation of 

aesthetics, sustainability, and efficacy, 

making the earth-sheltered homes 

viable over the long-term with its 

minimal moisture uptake (less than 1%) 

and low U-value. 

“Offering architects this ultimate 

flexibility to innovate was our goal in 

introducing the ULTRA 300 SL – the 

thinnest XPS insulation with a design 

lambda of 0.028 W/mK – and so it is 

brilliant to be facilitating a project with 

such potential for positive impact.” 

By combining Ravago’s Ravatherm XPS 

X ULTRA 300 SL insulation and triple 

glazing with three earth covered walls 

and roof, the homes have design SAP 

Ratings of 131A and 142A – meaning 

that on completion in May 2022 they 

will be in the top 0.01% of the UK’s 14 

million registered Energy Performance 

Certificates (EPCs). That’s something 



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

PROJECT FOCUS 


to make you sit up and take notice. No 

compromises were made by technical 

consultant Dr Harrall, who, keen to 

achieve outstanding SAP ratings, chose 

to use Ravago’s higher performing 

ULTRA insulation as well as install a 

thicker than required board. The board 

is available in a range of thicknesses 

from 80 to 205mm, has high 

compressive strength and high loadbearing 

capacity. 

In this case, boards were double layered 

to a width of 335mm in the floors and 

roof and a single layer of 205mm was 

used in the walls. This project has cut 

no corners to create extremely highperformance 

low carbon housing. 

Another unique element of the project 

is the greenfield site location. Getting 

permission to build on a greenfield site 

is rightfully challenging, and initially 

proposals put forward by landowner 

Dr Christopher Parsons were rejected. 

However, in 2018, permission was finally 

granted on the basis that the homes 

would contribute to the economic and 

social fabric of the village, as well as the 

biodiversity of the area. 

But this development has undeniable 

potential to contribute to not just 

village life but wider society, presenting 

a blueprint for future developments 

built on greenfield sites elsewhere 

across the country. And although these 

21st century homes present a hopeful 

vision for the years ahead, they are 

also founded on the Vales’ decades 

of tenacious research, progressive 

thinking, and industrious pragmatism. 

Ravago Building Solutions has a 

similarly strong heritage; Ravatherm 

XPS X products are made and 

despatched from King’s Lynn in Norfolk, 

where Ravago Building Solutions began 

making the UK’s first-ever range of XPS 

insulation products over 60 years ago. 

Sustainable housing might not be 

anything new, but Howgate Close is 

a mark that housing developments 

certainly don’t have to be the same as 

they always have been. 

“I think this could be the future of 

sustainable rural architecture”, says Dr 

Jerry Harrall, a leading fossil fuel-free 

designer who consulted on the project’s 

energy efficiency, detailing, monitoring 

and ongoing research. 

“Dr Parsons’ vision for Howgate Close 

as a replicable model has the potential 

to provide both rural housing and 

wood pastures for every village in the 

country.” 

Contact Ravago 

Building Solutions 

www.ravagobuildingsolutions.com 

Tweet: @RInsulationUK 

Images: Ravatherm XPS X ULTRA 300 SL 

insulation has been specified for Howgate 

Close, making the earth-sheltered homes 

viable over the long-term with its minimal 

moisture uptake.

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. 

3 | Working Towards Zero Avoidable Waste in the Roofing Sector 

NFRC trade 

membership benefits 

NFRC supplier 

membership benefits 

Call 020 7638 7663 or visit 

nfrc.co.uk/Greenscapes to request our 

benefits brochure—and find out more 

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NFRC GROUP ALSO INCLUDES 

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SOLAR PV ADVICE 

KEY CONSIDERATIONS 

FOR PV PROJECTS 

By Stuart Nicholson, Roof Systems Director at Marley. 

The UK’s net zero strategy and 

ambitious carbon reduction 

targets in both the new Part L 

and the Future Homes Standard are 

driving increased demand for solar 

PV. In fact, figures from Solar Energy 

UK, show that 2020 saw a 27% yearon-year 

increase in new solar capacity 

in the UK, with 40% of this increase 

coming from solar roofing installations 

on homes and commercial buildings. 

While for many people, solar PV still 

brings to mind images of large bulky 

panels sitting over the top of roof 

tiles, advances in technology means 

there are now many more design-led 

options available, at a much more 

affordable price. So how do you select 

the right solar product and what 

other considerations are there when 

embarking on a PV roofing project? 

There are several key decisions to make 

when designing or installing a solar 

PV system which depend on several 

factors, including the type of building 

and roof covering, size, pitch, amount 

of electricity required, aesthetics, and 

planning. 

1Choosing a solar product: on-roof 

or integrated? When it comes to 

solar PV, there are three options to 

choose from: a traditional on-roof panel, 

or two different types of integrated PV 

system (one with a separate tray and 

one with an integrated tray). 

Many people associate solar panels 

with the original on-roof systems, which 

consist of a set of panels attached 

to the rafters by a mount, sitting 

over the top of the roof tiles. These 

can stand out too much, so modern, 

integrated solar PV systems have been 

developed, which blend in seamlessly 

with roofscapes. These roof integrated 

panels are designed to be incorporated 

into the roof surface, acting as an MCS 

012 approved building material, and 

effectively replacing a section of tiles. 

They fit in with the existing roof tiles to 

become part of the design. 

There is a belief that on-roof systems 

generate more electricity. However, 

the difference is relatively small and 

is outweighed by some of the other 

disadvantages of an on-roof system, 

particularly because they can look quite 

bulky. Other disadvantages include the 

way they are attached, which can lead 

to water ingress and nullify the roof 

tile manufacturer warranty; the extra 

weight, which can lead to unnecessary 

strain on the roof structure; walking on 

a completed roof to install them could 

lead to hairline cracks in the tiles, whilst 

birds’ fondness for nesting in the panels 

can also cause issues. 

Modern roof panels are sleeker 

than in the past, but they hold no 

comparison to the aesthetic of roof 

integrated PV. As both tiles and PV are 

installed together, it means there is no 

modification to the roof tiles, securing 

the warranty. Our integrated Marley 

SolarTile system is compatible with all 

our clay and concrete tiles, so you can 

easily incorporate solar PV into any roof 

design. 

To make it easier to install more power 

output, we have just launched a new PV 

panel. The enhanced Marley SolarTile 

is quick to install, and the increased 

efficiency allows for an install time of 

just 45 minutes per kWp. 


2Choosing an integrated PV 

system: with or without a tray? 

Most integrated PV systems 

require a separate carrier system for 

the panel to sit into. These tend to be 

in the form of separate polypropylene 

trays. The main disadvantage of this 

system is that it requires additional 

timbers to fix to, as well as counter 

battens. Fire retardant trays are 

available but often come at a higher 

cost. 

The other option is a solar PV with 

integrated tray system, such as Marley 

SolarTile. These systems sit directly 

onto the battens and, in some cases, are 

fixed to the rafters and the battens. This 

means wind resistance is significantly 

higher due to the direct fixings. As the 

aluminium tray is integrated into the 

panel, fire ratings are also often higher 

than the plastic tray systems. Although 

initial purchase price can be higher, 

when the prices are inclusive of extra 

timber and labour, alongside the extra 

cost for the fire-retardant tray, the 

integrated system can be more cost 

effective. 

3Monocrystalline v 

polycrystalline 

Both monocrystalline and 

polycrystalline solar panels serve the 

same function in the overall solar PV 

system: they capture energy from the 

sun and turn it into electricity. They 

are also both made from silicon, which 

is used for solar panels because it is 

an abundant, very durable element. 

Many solar panel manufacturers 

produce both monocrystalline and 

polycrystalline panels. Monocrystalline 

solar panels are generally thought of 

as a premium solar product. The main 

advantages of monocrystalline panels 

are higher efficiencies and sleeker 

aesthetics. 

4Property and roof suitability 

Property and roof suitability is 

a crucial aspect which needs 

to be considered before specifying 

and installing solar panels. A lot of 

these considerations will be addressed 



SOLAR PV ADVICE 


through onsite surveys and include 

the orientation of the property, with 

south being optimal for maximum solar 

returns. 

Surveys should also look for potential 

shading factors which surround the 

property, such as large trees and other 

ecological considerations which could 

provide shading and therefore reduce 

panel efficiency. This can also include 

neighbouring properties or even in roof 

aspects, such as chimneys and aerials, 

which can cause shading. Pitches of 

roofs can also be something to identify 

pre-planning, as solar panels are at 

their optimum from 30-40 degrees, due 

to the sun’s location. 

5 

Permitted planning 

development rights 

The installation of solar 

panels and equipment on residential 

buildings and land may be ‘permitted 

development’ with no need to apply 

to the Local Planning Authority 

for planning permission. There 

are, however, important limits and 

conditions which must be met and 

you should check these with your 

Local Planning Authority. Importantly, 

permitted development rights for solar 

do not apply to listed buildings, so 

these projects would require planning 

consent. 

6Size of solar array The size of 

solar array you install will depend 

on several factors, including 

available roof space and household 

electricity usage. A well-sized PV solar 

energy system can cover a significant 

portion of a home or building’s annual 

electricity usage, up to 65-75% in many 

cases. 

The innovative technology used in 

our new Marley SolarTile gives the 

benefit of an increase in total power 

output from the roof area or achieving 

the same output using fewer panels. 

A higher power rating makes roofintegrated 

solar a more cost-effective 

option, with fewer panels and roofing 

kits needed to reach the required 

energy target. 

Estimating is a simple process, as our 

online configurator builds an array of 

panels for you (www.marley.co.uk/ 

solarinstall). All you need to do is fill in 

the grid to place the panels in position 

and the system works out which 

flashing kits are needed and produces a 

price. It even calculates the kWp output, 

so you can easily achieve the required 

performance. Or if you’re a specifier 

and need a full roof specification, 

you can email our technical team at 

roofing@marley.co.uk 

Contact 

Marley 

Tel: 01283 722222 

www.marley.co.uk/solarinstall 

Tweet: @MarleyLtd 


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Assured standards 

Meets all British Standards and regulations 

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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 

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Need a complete 

roof system? 

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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

Autumn '21

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