Workplaces with landscaped gardens are definitely beneficial for employees as these green spaces offer them an opportunity to sit and relax amongst living plants in the midst of a busy workday. However, many businesses simply don’t have room for a breakout area in an outdoor space. Such workplaces can consider adding a rooftop garden to create a welcome green space for their employees.

Several businesses are transforming their rooftops into small gardens and ‘green’ spaces for their employees to unwind and enjoy their lunch in the sun without having to even leave the building. Being able to enjoy some time amongst nature has a huge array of benefits, and can even help to boost productivity.

Structural considerations and approval

Businesses planning on creating a green space on their rooftops would do well to consider a few things before heading off to buy plants and supplies.

For instance, they will need to ensure easy access to the rooftop, and have the space approved for pedestrian traffic. The waterproof membrane on the roof will need to be protected from the garden. Sufficient care should be taken to avoid piercing the rooftop membrane as it can cause leaks.

Since the rooftop garden is designed for the enjoyment of employees, one will need to take the weather elements into consideration, especially windy conditions and heat exposure. The space will have to be designed with sufficient protection to block out the elements if required.

Very importantly, have a structural engineer confirm the load capacity of the roof since it will need to support garden beds and water tanks. Some roofs are not designed structurally to carry the amount of weight needed for a rooftop garden; a professional assessment prior to start of work is, therefore, recommended.

All rooftop gardens need secure railings around the edge. Objects should not be placed close to the railings as they could pose a potential hazard. The local council will have regulations governing the height of railings in such applications. A water source for the rooftop garden should also be integrated into the design plans.

Council approval should be sought to ensure feasibility of the rooftop garden plan. The council should also be able to provide detailed information about public safety issues and other requirements for the rooftop garden.

Design considerations

Considering the rooftop location, one should choose plants that require minimal watering so as to avoid the risk of water pooling on the roof. Succulents are a great option for rooftop gardens as they’re low maintenance, don’t need much watering, and enjoy lots of sun. An edible garden with veggies and herbs is also an excellent idea for rooftop green spaces.

In terms of shade options, one could consider a motorised or cantilevered umbrella or a few shade sails. The final choice will depend on typical wind speeds in the area and how the sun hits the rooftop. Outdoor seating and tables also need to be able to weather the elements and remain secured to the rooftop. Integrating elements such as a giant chessboard or ping pong table can add some fun to the rooftop garden. Consider a barbecue too if there’s space.

If the rooftop is unable to withstand the weight of a complete garden, consider container gardens that don’t weigh much. When assessing weight, always think of how heavy the soil will be at its wettest.

If rooftop waterproofing is found to be inadequate after the initial inspection, it can be easily remedied by having a professional fix or change the waterproofing membrane so that it’s suitable for the rooftop garden.

In addition to serving as an excellent breakout area for building occupants, rooftop gardens also help to insulate the building and even control stormwater runoff. Rooftop gardens can also extend the life of the roof’s waterproof membrane.

Projex Group is the Australian and New Zealand distributor of the Wolfin, Cosmofin and Koster range of waterproofing systems.