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

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.

Conclusion

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.