THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN 4  ONTARIO ROOFING NEWS – WINTER 2018/19 Every project comes with its set of known, as well as unanticipated, challenges, and this one was no different. Cover Story less daunting, the design team, in consultation with the construction team, chose a LiveRoof pre-vegetated modular green roof system for the green roof. With the green roof area sloping at a 10-degree angle toward the north, partially in the shade and being a prominent feature of the Indigenous Commons as well as highly visible from all interior levels of the new DARE District Building, it was important to have a system that guaranteed both quick installation and good plant estab- lishment prior to installation. OIRCA member LiveRoof Ontario worked closely with the design- ers to select the plants and layout of the plantings on the roof. Na- tive species of plants suitable for a 150mm deep modular green roof system, in part shade, were selected along with a living mulch of very low growing Sedums. Twenty-one different species of plants were used in various combinations to create a pleasing design reminiscent of an Ottawa Valley native wildflower meadow. LiveRoof’s unique modular green roof system allowed for all the plants to be grown in their final positions off site at the LiveRoof production nursery near London, Ontario. This ensured that the plants had the level of establishment and maturity that ensured rapid adaptation to the roof environment at their new Ottawa home. Production of the green roof modules began in fall 2017, the modules were overwintered at the nursery and then finished and delivered in early July 2018 once the build- ing, the roof and the slope restraints on the roof were ready for the green roof installation. Because both the Indigenous Commons and the green roof are located in a courtyard surrounded by college buildings, new and existing, all materials had to be craned into and out of the courtyard over top of the newly constructed building from the staging area beside the building, a reach of about 225 feet. Careful coordination between Simluc’s operations manager and the landscape contractor allowed the green roof installation to dovetail seamlessly with the landscape contractor’s needs for the crane. A large counterweighted 250-tonne crane with two expert operators, capable of landing materials within inches of the building façade, was set up to accommodate the materials and equipment movement into and out of the courtyard for both the green roof installation and the landscape work. Because of the height and the width of the building, the crane operator was landing his cargo blind at the other side of the building, and was relying on the other operator for precision. Every project comes with its set of known, as well as unantici- pated, challenges, and this one was no different. While the crew knew that the roof slope was go- ing to be physically challenging and prepared accordingly, high winds on the second day of in- stallation brought the craning to a halt after only a few lifts. Ar- rangements had to be made on the fly to accommodate the two remaining truckloads of racks full of green roof modules that had arrived on site to be installed. After the craning delay the green roof was finished smoothly with all the perimeter edging installed and soil elevators removed. Once the soil elevators were removed, the individual modules were no longer visible, and the green roof looks like it has been there all along. The irrigation system was installed next. Because of the slope of the roof, the height of some of the plants and the requirement to use stormwater from a cistern, it was decided during the design phase that a drip irrigation system would be the best choice of irrigation system for the project. While the green roof is in shade for a significant portion of the day, and the plants have been selected accordingly, there is still a requirement for regular irrigation of these green roof plants. Only succulent plants such as Sedums can reliably be installed without an irrigation system. The native woodland edge plants used to create the wildflower meadow have water use requirements that are simply too high in mid- summer to leave the watering solely to rainfall. Fortunately, the use of stormwater for irrigation is a strategy that is encouraged by the LEED consultants as well as the City of Ottawa and the local Conservation Authority. It is part of an emerging strategy to reduce stormwater runoff by reuse of the water for irrigation at the development site. Nutri-Lawn installed and acti- vated the drip irrigation system shortly after the green roof instal- lation. Ironically, after the two hottest and driest weeks of the summer in Ottawa prior to and during the installation, regular thunderstorms, sometimes very heavy, started as soon as the irri- gation system was operational. The finishing touch to the green roof was the addition of Mexican black pebbles in the vegetation-free zones to cover the remaining exposed roofing mem- brane along the sides and around the fall arrest anchors and the life safety line at the top of the green roof slope. The green roof is now in its first Ottawa winter, and from all observations to date it is going to be a nice new addition to the green spaces at Algonquin College. The project’s ongoing maintenance is coordinated The green roof from the courtyard, complementing the Indigenous Commons. The finished green roof in October 2018, with fall flowering plants on display. For over 60 years, we’ve been the number one name in customer service. DELIVERY IN THE GREATER TORONTO AREA www.lbsupply.ca | 416 420-5051 Commercial or residential, pick up or rooftop, special order or stock we are your one stop shop for roofing material. If you need it, we have it in stock at the right price.