Did You Think That Green Roofs Are Only For Specialist Contractors? Think Again!

Thought green roof installations were only for specialist contractors? Then think again, think green and think new business opportunities! From domestic garage roofs to office developments, hard-to-reach areas on residential blocks, hospitals and city centre hotels, almost any flat roof can be considered for greening thanks to the introduction of modular green roof systems which are quick and easy to install.

Go Modular!

Go modular and there’s no need for the traditional roll-out build-up of a root barrier, drainage layer, textile filter and growing medium. Instead, delivered to site will be plastic trays filled with growing medium and pre-planted with sedum or wildflowers. Simply lay geotextile fleece on to the roof finish, place the trays and click together. Border pebbling completes the look. To coin a well-used phrase, job done (400m² of it in one day for a two-man team is more than possible).

It is, quite literally, a growing market and one that British manufacturer Wallbarn has invested in heavily to develop its market-leading M-Tray solution. The Croydon-based business, which has been supplying specialist products to the construction industry for 40 years, is a pioneer of modular green roof systems. Its most recent success is a unique 100mm deep plastic cassette filled with scientifically developed substrate and carefully selected sedum and wildflower plants grown to maturity on its own farm in Hampshire.

Offering A Variety of Benefits

The modular approach offers a number of really valuable benefits, not least that most construction professionals are more than adequately equipped to carry out installations. It is, therefore, a great opportunity for building contractors to expand their domestic and commercial portfolios and meet client demand for more environmentally friendly buildings; green roofs provide additional insulation properties and are proven to improve air quality, absorb and slow down rainfall, provide urban cooling, prolong the life of the roof, increase biodiversity and support an array of wildlife.

So what do you need to know to get started?

The first question: can the roof support the additional weight of the green roof? This must be answered by a structural engineer and is the first consideration for any green roof, modular or roll-out. M-Tray can be retrofitted onto the vast majority of existing roofs (the standard system weighs up to 120kg/m² fully saturated). For new-build projects, the required structural integrity can be designed in.

The design: simply calculate how many 500mm x 500mm M-Tray cassettes are required for the roof area to be greened together with the quantities of geotextile fleece and border pebbling. Wallbarn technical experts can assist, advise and draw up plans if required, which we find is particularly useful for first-time users of our product. We also provide on-going technical support.

The installation: The cassettes contain everything that the green roof requires, from built-in drainage to 100mm of the specialist substrate and, of course, the plants (Wallbarn has just launched a native perennial wildflower option, allowing clients to enjoy a hardy, beautiful haven for pollinators).The clean and easily transportable pre-planted trays can be carried by hand and have even been passed through windows on hard-to-access roofs. They sit on a geotextile fleece which protects the existing roof/membrane and simply click together to form an instant green roof. A really important feature of modular green roofs is that the roof is future-proofed because the cassettes can be lifted up at any time should access be required to the roof deck.

The maintenance: Sedum plants are hardy and will tolerate extreme conditions – there are green roofs worldwide thriving in a wide variety of climatic conditions, some of them 75 years old or more. In exceptionally dry conditions it may be necessary to water the roof; some clients choose to install an irrigation system and apply slow-release fertiliser for best year-round results.

Technical considerations: Fire regulations require a hard border between vegetation and building walls and around features such as rooflights and fall arrest systems (consult the GRO Code for further details). The roof also needs to be relatively level; M-Tray can accommodate slopes of up to 15° but we do not recommend going above 10° without anchor points or battens.

Availability: Wallbarn offers year-round supply and often next day delivery direct (on orders placed before 2pm) or through one of our merchant partners.

Thanks to technologically advanced modular solutions undertaking green roof installations is no longer the preserve of specialist contractors. It is a win-win solution for building contractors – as well as offering clients large and small a fuss-free green roof that looks great, encourages biodiversity and meets environmental agendas – it helps with planning applications and provides a new revenue stream for the contractor.

Take a look at a video overview of the M-Tray system from Wallbarn.