M-Tray®: the smart solution for successful green roofs

Green Roof Installation

Wallbarn’s award-winning M-Tray® green roof system quickly delivers beautiful, established living roofs for the hardest to reach domestic and commercial roof top locations and where clients demand retained access to roof decks.

M-Tray’s® secret lies in its modular approach – every element of a traditional roll-out green roof (drainage, root barrier, substrate, plants) is cleverly contained within each 500mm x 500mm x 100mm M-Tray® click-fit polypropylene tray. Contractors need just one delivery to site, can easily hand-ball trays to reach the most difficult to access roof areas and simply remove the trays if roof deck access is required at any point in the future.

This one-stop-shop solution to greening delivers a system that is incredibly clean and easy to install, straightforward to specify and quick to order, with just-in-time delivery from Wallbarn’s Hampshire nursery available overnight if required.

M-Tray® is, we believe, the most innovative and highest quality extensive green roofing solution on the market and suitable for most, if not all, flat roof projects. It also boasts impressive eco credentials, with almost every element of the system sourced in Britain and as close to Wallbarn’s nursery as possible.

The tray: Manufactured in the UK from recycled polypropylene. To aid installation, each tray has hand grips to aid lifting and connectors that knit the units together tightly & securely. Corners are rounded to avoid sharp edges. Drainage holes are strategically placed to ensure beneficial water retention to prevent plants dying back at the edges. At 100mm deep, the trays provide optimum space for healthy roots and plants.

The substrate: The correct substrate composition and volume is of prime importance. Wallbarn moved away from brick-based aggregate mixes towards horticultural solutions whilst taking into account recommendations and limits on organics and other ingredients as laid out in BS 8616 & the GRO code.

The result is an extra deep growing medium that offers optimum levels of nutrients and aeration supported by suitable drainage. The substrate is environmentally friendly being free of peat (peat also shrinks over time, affecting plant performance). M-Tray utilises coir (a waste product from the coconut industry), green compost and recycled lightweight aggregate.

The plants: Wallbarn offers two variants of M-Tray® – a traditional flowering sedum selection & a new-launch native, perennial wildflower option. Both offer a mix of plants which give comprehensive coverage and flowers at different times of the year.

The system: Production at Wallbarn’s nursery in Hampshire is highly automated. The trays are mechanically laid onto nursery beds and evenly filled with substrate with Wallbarn’s own specially designed equipment before hydroseeding adds the final element. The trays are constantly monitored and quality checked during the growth phase and grown on in-situ for at least nine months until mature enough for dispatch. A specially designed mechanical picker ensures the plants are not damaged during harvest. This process ensures only established & healthy vegetation reaches site.

Sustainability: The basic premise of M-Tray® (pre-grown trays that offer a complete green roof system) makes it highly sustainable because quality is tightly controlled ensuring optimum plant health and long life. On-site wastage is minimal and road miles are kept to a minimum through the use of British-grown sedum. Home-produced recycled/recyclable plastic trays, peat-free substrate, environmentally friendly recycled lightweight aggregate, local green compost and coir, a by-product of the coconut industry, all further boost eco-credentials.


Green roofs have many benefits, including aiding biodiversity and creating habitats for flora and fauna (most notably pollinators; a study of green roofs in London recorded more than 20 species of bee foraging on them), managing storm water run-off, improving air quality, reducing the urban heat island effect, improving local air quality, sound and thermal insulation, extending the lifespan of waterproofing membranes and even boosting the mental well-being of those looking out on to them.

M-Tray® is a straight-forward one-stop-shop solution which simplifies the traditional approach to deliver fully established green roofs in a fraction of the time it would take to install roll-out systems. Wallbarn technical experts are on hand to answer questions and offer advice if required. Investment in the product is recouped from on-site time and labour savings as well as better utilising the building footprint, achieving environmental targets and enhancing the building’s value.



Green Roof Day Is Coming Back……

It is with great excitement that we look forward to the second annual World Green Roof Day taking place on the 6th June 2021.

This new annual day of celebration belongs to the world of green roofing and is the perfect opportunity to share images, projects and case studies of all the fantastic green roof and roof garden projects around the globe.

To engage with World Green Roof Day on social media just use the hashtags #WGRD and #WGRD2021 on the day and in the run-up to it.

World Green Roof Day

What is #WGRD?

A celebration of green roofs all over the world and the benefits they bring to people and nature.

Why #WGRD?

Towns and cities globally are going green to adapt to climate change. Green roofs also provide vita wildlife habitats and make life better for everyone.

How to be part of #WGRD2021

Share the green roof love on social media with images, events and gatherings.

Become a #WGRD2021 supporter

You can support #WGRD2021 as an individual or organisation

We believe World Green Roof Day is a tremendous idea by the team over at Bridgman Landscapes and encourage everyone to get involved.

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The loss of vegetation is creating a dangerous heat island over Nairobi

flowering native sedum

Kenya’s capital city, Nairobi, used to be known as the “Green City in the Sun” for its lush environment. There have been however recently been a lot of changes to Nairobi’s land cover – what’s on the ground’s surface. Most recently, there was uproar over the felling of hundreds of trees to make way for the construction of the Nairobi Expressway. Moina Spooner, from The Conversation Africa, asked Victor Ongoma and Patricia Mwangi to share their insights into how changes in land cover affect the city and its environment.

How has land cover changed in Nairobi?

Nairobi is one of the fastest growing cities in Africa. The city’s population, which was about 2 million people a decade ago, now stands at over 4 million. This puts a lot of pressure on the natural environment.

Areas of vegetation around rivers and forested land have declined in the city due to encroachment and infrastructure development, namely roads and buildings. It has been reported that Nairobi city has lost 22% of the city’s green spaces cover in the period between 1988 and 2016.

Changes in land cover in Nairobi are mainly due to policy changes – such as zoning – that increase the plot area covered by a building relative to the total plot size. For instance, areas close to the central business district that were residential in land use have seen recent conversions to commercial or office space land use. This changes the landscape.

In what ways has this affected the city and its residents?

Areas covered by impervious surfaces such as tarmac, metal or concrete – have higher surface temperatures compared to vegetated land cover. This is because vegetation provides shade and, through evapotranspiration, cools cities. Impervious surfaces such as concrete absorb more solar radiation than they reflect. This leads to a phenomenon known as urban heat island.

Urban heat island refers to when temperatures in the city are higher than those of surrounding areas that have more vegetation cover. The effect is more pronounced at night when impervious surfaces re-radiate heat that is absorbed during the day into the atmosphere.

Through our work, we have found that an urban heat island is already manifesting over Nairobi. Data over Nairobi indicates that average air temperatures increased from 18.8°C in the 1950s to 19.5°C in 2000s. This situation is likely to become more pronounced given the ongoing environmental modification by construction, such as the Nairobi Expressway.

What are the implications?

This urban micro-climate will have an influence on the quality of life of city residents. Although the intensity of Nairobi’s heat island has not reached alarming levels of directly causing death, with ongoing developments this is bound to eventually happen.

The most direct effect on health from the urban heat island is heat health risk. Heat can worsen pre-existing conditions such as heart and lung disease, kidney problems, diabetes, and asthma. It can also affect occupational performance or lead directly to death. Extremely high temperatures of more than 27°C for a period of time, such as during heat waves, puts people with health issues particularly at risk.

At certain times of the year, parts of Nairobi are already dealing with temperature increases of up to 4.8°C and are associated with increases in mortality, especially in children and the elderly. Residents of large informal settlements – such as Kibera, Mathare and Mukuru – are more vulnerable due to population density and housing infrastructure that is characterised by poor ventilation. The urban heat island will worsen conditions such as respiratory issues and heart diseases caused by household air pollution in these settlements.

Also, because it gets hotter, urban heat islands cause thermal discomfort. To counter this, more appliances – such as electric fans and air conditioners – are used. This leads to an increased consumption of electricity on cooling in buildings. The increase in demand and consumption of electricity has financial implications at a household level and increases carbon footprint in the atmosphere.

For more on this story, please click here.

London hotel with Europe’s largest living wall approved

Installing M-Tray green roof

At 40,000 sq ft, the living wall at the proposed Citicape House will be incorporated into the facade of the 11-storey building and will easily be the largest in Europe, almost double in size to its next closest competitor the National Grid Headquarters.

Architect Sheppard Robson has designed the 5-star hotel which will replace the existing 1960s building at 61-65 Holborn Viaduct in the city.

Developer Dominvs Group has been in talks with McAleer & Rushe about the construction plan. This will involve oversailing two existing Network Rail tunnels in the basement of the building using a mix of both in situ concrete and steelwork.

Jay Ahluwalia, Dominvs group director, said: “Dominvs Group is incredibly proud of our proposals for 61-65 Holborn Viaduct which aim to play a major role in the regeneration of the Smithfield area.

“With the City of London’s vision for the area and the creation of the Culture Mile, we feel this project will support and enhance the overall ambition for this exciting, new cultural destination as the creative heart of the Square Mile.”

The development will also include a roof-top viewing gallery on the 11th floor, which will have views overlooking St Paul’s Cathedral and the Grade I-listed St Sepulchre’s Church.

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Fines to pines: London’s first urban forest to rise above former Blackfriars Crown Court

M-Tray sedum green roof Radisson hotel in flower

A disused London court building is to undergo a “fines to pines” transformation that will see its rooftop turned into London’s first urban forest.

Designs approved by councillors show how the former Blackfriars Crown Court show how 100 established trees and 10,000 plants will create a 1.1 acre woodland high above the streets of Southwark.

The site on Pocock Street, where justice was once handed out in eight courtrooms, was sold to the property investor Fabrix for a reported £65 million last year.  

The 1960s building, which opened as a court in 1993 when it was originally known as Knightsbridge Crown Court, will be turned into 385,000 sqft of office and community space known as Roots in the Sky. 

The first two storeys will be retained and six new levels will be created above using a steel and timber frame strong enough to support 1300 tonnes of soil with 1.5-metre deep tree pits.

As well as the forest it will have a publicly accessible rooftop restaurant and bar and an infinity pool heated by the building’s waste. It will have a glass bottom allowing swimmers to peer into the workspaces below.

Fabrix chief executive Clive Nichol said: “This building anticipates the shift in the way people are thinking about their working life post-COVID. It’s designed with generous spaces and natural ventilation, access to nature and a mix of uses that reflects new ways of working and living.  

“For us community use goes further than a coffee roastery – it’s about creating daily connections between the neighbourhood and those using the building for work and leisure. We hope that Roots in the Sky serves as a statement on the value of sustainable, community-led development.”

Please click here for the full story.

European Parliament Highlights Green Roofs For Climate Change Adaptation

Sedum green roof summer flowers

December 2020 – In a resolution adopted on 17 December the European Parliament recognised the key role of green roofs and walls to minimise the adverse impact of climate change.

The resolution says that green roofs and walls can contribute to cooling high urban temperatures, retaining and reusing rainwater and producing food. Urban green infrastructure can also help reduce air pollution, improve the quality of life in cities, reduce risks to human health, and protect biodiversity, including pollinators.

MEPs supported any targeted initiatives to seize this potential, including the development of urban strategies and better spatial planning. Moreover, they called for infrastructure such as roads, parking lots, train tracks and power and drainage systems to be made biodiversity and climate-proof.

The Parliament’s resolution on adaptation to climate change will provide input on a new EU Adaptation Strategy, expected from the Commission in 2021 as part of the European Green Deal.


About us
The EU Chapter of the World Green Infrastructure Network (WGIN) aims to increase the awareness of the European Union policymakers about the multiple benefits of green infrastructure, with a specific focus on Building Integrated Vegetative Systems (green roofs and living walls).

WGIN brings together national and regional industry associations to promote the development of the green infrastructure industry through training, research, advocacy for new policy, conferences, publications, and promotion.

For the full article, please click here.


Fire Safety Armoury Strengthened By British Standard For Balcony Construction

Fire Rated Pedestals

A new British Standard introduced at the end of August is helping close what a growing number of building professionals have identified as clear gaps in the fire safety performance of high-rise residential buildings with balconies.

Fire Rated Pedestals

The release of BS 8579:2020 Guide to the Design of Balconies and Terraces is a welcome addition to the Government’s more robust approach to the fire safety of blocks of flats and supports the already-updated Building Regulations and Approved Document B.

The new standard states that all construction elements of balconies and terraces located more than 18m above ground level must be non-combustible, including structural joists, flooring and suspension etc. This means no wood, plastic, rubber etc. Importantly, the regulations now define balconies as part of the external wall, bringing them in scope of Part B and its more stringent fire safety requirements and ending the conflict that specifying to Part L placed upon fire performance.

Balconies have long been considered an important amenity, providing covered walkways or giving residents access to private outside space. Now, more than ever, that amenity is highly prized post-COVID-19 lockdown and it is likely that future new-build developments will be looking to incorporate them.

BS 8579 may be considered one of the regulatory responses to fires in residential multi-storey buildings, including Samuel Garside House, Barking, The Cube in Bolton and Worcester Park, south west London, but work on the standard began two years earlier than these 2019 blazes and several weeks before the Grenfell tragedy.

Social housing providers have taken note, with a number introducing balcony smoking bans (smoking materials, BBQs and arson are the main causes of balcony fires). The Home Group, which supports 125,000 residents nationwide, has produced a ‘Keeping your balcony safe’ leaflet and formed a fire safety tenant focus group.

Back in 2016, the issue was highlighted by the Building Research Establishment’s report – ‘Fire safety issues with balconies’ – compiled for the Department of Communities and Local Government following balcony blazes on high-rise residential buildings in 2010-2015. BRE reported that six balcony ‘fire incidents’ were reported in 2015 compared to one in 2005.

The report makes sobering reading, especially its references to one balcony set alight by a plastic cup used as an ashtray; the block of flats was predominantly a concrete construction with external surfaces “covered in a variety of cladding systems with cavities filled with a variety of rigid foam insulation”. The balcony floor was timber decking on timber battens covered with a woven plastic sheet over foam insulation. The sheet ignited and the fire spread to the foam insulation on the walls and under the decking.

This summer, the insurer Zurich called for balcony BBQs to be banned, stating that almost £9m of damage was caused in 2019 by just four balcony blazes which spread to neighbouring flats or entire buildings. Its research also revealed that in London alone there were 550 balcony fires in the last three years. “Modern methods of construction, including timber-framed buildings, combustible cladding, wooden balconies and modular units add to the risk of balcony fire,” added Zurich.

With the introduction of BS 8579 and the strengthened Building Regulations and Approved Document B banning the use of combustible materials in external wall systems and balconies 18m+, concerns about these construction methods should be answered. We are also seeing increasing numbers of clients opting to implement the new regulations at lower heights to ensure the ongoing safety of residents and assuage insurers rightly concerned about the huge cost to them of fires on balconies.

However, Wallbarn fears that efforts to improve the fire performance of buildings may create a risk that fully tested, established and quality – but not compliant – building solutions may be replaced by seemingly compliant but lower performance products. And that’s why we need to be absolutely sure that the industry is properly briefed to design, specify and build fully compliant and safe solutions.

Our sector – pedestal systems which support suspended balcony and terrace decking/paving – is a good example of this. Traditionally, pedestals were heavy-duty polypropylene plastic but to satisfy BS 8579, they will have to be metal when installed at height. These products are available – Wallbarn has developed MetalPad, an all-metal, Class A1-rated pedestal that is fully compliant with BS 8579 – but we know that systems have come to market which have rubber or plastic elements labelled as ‘gaskets’. To call a plastic headpiece a ‘gasket’ does not, in our opinion, conform to the standards and regulations.

We are also concerned about the quality and testing regimes of some metal pedestal solutions. From sampling the market, we know that not all products offer the level of performance we feel is required. Some pedestals have been modified from interior usage and are not designed for exterior applications. The small baseplates on some brands are cutting into surfaces beneath, compromising U-values and creating uneven, unstable paving areas. There is a real risk of jeopardising safety on schemes through the very task of trying to improve fire safety.

There’s also the question of product testing, a crucial factor given these systems are used at-height. Load-bearing is critical and we have heard reports that hollow stems can lead to collapse. Our advice is always to consult with your original supplier to at least understand the questions you should be asking of a new supplier. This is especially important in the light of Grenfell; recent witness evidence at the Grenfell Enquiry has revealed confusion about product performance, suitability and installation methods, highlighting the need for everyone to take responsibility throughout the supply chain. Do not assume someone else is doing it and always ask for – actually demand – test results.

Product provenance is a further issue to be considered. Recent industry talk suggests that imported product was rejected by two main contractors upon arrival at site due to quality concerns. It is good to hear that, despite the inevitable project delays and additional costs such action would have created, quality was considered more important. Again, our advice is to ask the right questions during specification to ensure that the chosen solution is designed for purpose, fully tested and supplied by a trusted partner.

For the full article, please click here.

10 projects to watch in 2021

Some huge projects are due to hit critical milestones in the new year, as coronavirus, social distancing and Brexit continue to dominate the delivery of construction projects in 2021. Here’s our run-down of the big ones to watch.


1) Forest Green Rovers stadium – a timber revolution?

Gloucestershire-based Forest Green Rovers’ decision to build a wooden football stadium was unprecedented. It has becoming an even bolder call when you consider the current perception of combustible materials and backdrop of financial uncertainty facing lower-league teams.

A director from Zaha Hadid, who designed the timber structure (above), told CN in February 2020 wood was a good material for stadium construction, being both low-carbon and conducive to an attractive design.

Planning approval for the 5,000-seater stadium was granted back in December last year and the government decided not to call the project in shortly before coronavirus struck. Since then, there have been claims that the stadium would take just two years to build.

Forest Green chairman Dale Vince has said there is unlikely to be football played there until 2023, but next year will be a crucial period for the construction of this unique project.


2) Rolls-Royce doubles down on mini modular nuclear plans

The government laid out ambitious targets for reducing the UK’s carbon emissions in 2020. An upshot of that was an increased enthusiasm for nuclear energy, which, while it might not be everyone’s idea of a clean solution, produces substantially less emissions.

Talks over a new multi-billion-pound facility at Sizewell C in Suffolk were revived by the government in December 2020, as it seeks to deliver on its promise to invest in the sector. However, an interesting alternative to big plants is a plan, led by Rolls-Royce, to build several smaller modular nuclear reactors.

The household name is reeling after carrying out a £2bn rights issue to stabilise its balance sheet and fend off the financial impact of the coronavirus pandemic. This situation has increased the importance of Rolls-Royce’s efforts to convince the government of the value of the smaller modular approach. Particularly as the airline industry, one of Rolls-Royce’s key markets, is struggling to deal with the impact of COVID-19.

Backing Rolls Royce in their efforts is Atkins, Bam Nuttall, Jacobs and Laing O’Rourke.

For the full list, please click here.

2021 looking positive for Building & Infrastructure

With the positive news of the last three weeks around vaccines and rapid testing, along with affirmation from the Chancellor that the UK will benefit from over £3bn in new housing and the establishment of the UK Infrastructure Bank, the construction sector can plan-ahead with more certainty than just a few weeks ago. 

The team behind the UK’s largest construction trade event, UK Construction Week, have been laying the foundations for the recovery, with a major London exhibition planned in May.  

UK Construction Week London (4 – 6 May 2021) will be a major catalyst for construction demand with exhibitions being proven economic drivers generating over £11bn in sales per year.

2021 will see unprecedented construction activity as the sector catches up on delayed projects and capitalises on record government spending on housing and infrastructure. This eventy will come at a key time when the industry not only gets back on it’s feet, but take up the challenege of reinvigorating the UK economy post pandemic. 

We have two UKCW Spotlight days planned in advance of our main event in May to connect the supply chain.

UKCW Spotlight: Net Zero Housing – 9 March
A one-day event exclusively designed buyers of construction products and services for the housebuilding sector.

UKCW Spotlight: Sustainable Infrastructure – 16 March
A one-day event designed for civil engineers and contractors involved in buying construction products and services for the infrastructure projects.

Both events will give the buyers access to online content, and a chance to meet suppliers ahead of the main event in May. Successful relationships are about touch points, and this targeted event will allow exhibitors to create new prospects and strengthen existing ones ahead of the first live construction event in over a year.

Anyone interested in attending these two events should register their interest asap as places will be limited. 

Suppliers wishing to take part should; also note there will only be 30 places available. 


For more on this story, please click here.

LGA – COVID-19 has devastated councils’ park services

flowering native sedum

Parks proved to be a lifeline for local communities during the COVID-19 crisis but the pandemic has had a devastating impact on councils’ park services, the Local Government Association sets out today.

A series of case studies, co-funded by the LGA and the National Lottery Heritage Fund, shows that as much as 87 per cent of external parks and green spaces income is forecast to be lost due to the coronavirus.

Although almost all parks were able to remain open during the first lockdown, key sources of external income were forced to close, and many have been unable to return to their normal operations, including cafes, sports pitches and visitor attractions.

Despite many facilities reopening, it is anticipated that there will be a continued loss of income due to the need to employ more staff or reduce visitor numbers in order to comply with social distancing guidelines, and many council parks services have incurred additional operating costs relating to signage, Personal Protective Equipment and enhanced cleaning.

As well as income generators, the pandemic has resulted in the temporary cessation of volunteering and the loss of in-kind volunteer contribution to parks services ranging from £12,000 to £1.56 million across the case studies.

With the Government investing £2 billion in active travel, it is crucial that parks and green spaces are fully connected to these plans to maximise their potential to encourage physical activity and improving mental wellbeing.

Parks can play a key role in the national COVID-19 recovery and that is why the LGA is calling on the Government to confirm that they are included in the new Levelling Up and UK Shared Prosperity Funds, to enable councils to invest in new parks facilities, pitches and green spaces to reduce obesity; ensure a healthier, more active nation; and reduce our carbon footprint.

Cllr Gerald Vernon-Jackson, Chair of the LGA’s Culture, Tourism and Sport Board said:

“Parks have always been an important part of our communities, but the COVID-19 pandemic and subsequent restrictions highlighted how essential they are in maintaining our physical and mental wellbeing.

“It is easy to forget that parks are more than green space and contain a wealth of income generators, many of which have been impacted by the coronavirus and will continue to feel the effects for years to come.

“The list of benefits, not just to people but for wildlife, fauna and air quality, cannot be overstated. It is crucial that the Government ensures our beautiful parks receive investment for preservation and enhancement.”

Notes to editors

  1. The case studies are included in the full report Financial impact of COVID-19 on parks (2020-21).
  2. This research was funded by the Local Government Association and the National Lottery Heritage Fund and undertaken by Community First Partnership (CFP).

For more on this story, please click here.