This large-scale green roof installation, spanning more than 1,200 square metres, was delivered in collaboration with Polyroof / Roberts Manufacturing. Originally specified as a rollout green roof, the architect on the project expressed concerns around fire compliance. Wallbarn was able to confidently confirm that its M-Tray® modular green roof system had undergone physical fire testing and is certified to B Roof(t4) standard—giving full assurance of compliance with current fire safety regulations.

The M-Tray® system offered additional benefits that supported a specification change. Its modular nature enables futureproofing, as trays can be lifted individually for maintenance without disturbing the rest of the roof, and it allows for much faster installation than traditional rollout systems. These advantages led the architect to revise the original specification in favour of M-Tray®.

Due to the pitched roof and scale of the project, Wallbarn advised installing horizontal battens and structural parapets to prevent green roof slumping. The weight of a rollout system across such a large pitched area could lead to slumping, slippage or membrane stress at the edges over time. The recommended structural details were fully integrated into Polyroof’s Protec liquid waterproofing system, ensuring the membrane’s integrity was not compromised at any point.

Logistics were another major consideration. The site was located in a busy industrial estate with restricted access and no road closures or dedicated loading bays. A total of over 5,000 trays were needed to complete the roof. Wallbarn coordinated a delivery schedule over four weeks, harvesting and loading trays in batches of 640—three times per week—from its farm. These were delivered in articulated lorry loads to site in a tightly controlled sequence. Nia in our Logistics Department maintained constant communication with Haran Roofing, Polyroof, and the transport provider to ensure seamless execution of every drop.

The result was a high-performing green roof system, installed on time and to specification. The client, along with Polyroof and Haran Roofing, were delighted with the final outcome. The project has since been nominated for multiple roofing and landscaping awards, highlighting the exceptional planning, collaboration, and technical excellence involved.