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Cleveland Rooftop by SJB & William Dangar | Image: Felix Forest

We’ve seen some impressive rooftop gardens over recent years and with outdoor space becoming a premium, we’re sure we’re going to be seeing a whole lot more.

But if you think rooftop gardening is as simple as planting up a few pots with plants and arranging some outdoor furniture, you’d be wrong. A rooftop environment is harsh. You’ve got to contend with wind and heat, and you’ll need to consider the drainage, access and structural integrity of your outdoor space before you start building your rooftop garden.  All that aside, creating an urban garden in the sky is a great way to use an otherwise neglected space.

5 Rooftop Gardening Considerations

If you’re looking to green up your rooftop space, here are the top 5 rooftop gardening considerations.

1. Finalise your plan before you build

Whether you’re looking to simply decorate your rooftop with pots and furniture or want to do a complete overhaul of the outdoor space, finalise your plan before you start. You may also require approval from your Owner Corporation if applicable. At the planning stage, questions about building height restrictions, accessibility and fire regulations should be discussed.

It’s also worthwhile at this stage consulting with a building engineer to understand your rooftop’s load-bearing capacity. This will ensure your roof can safely support the weight of the soil, mulch, plants, water, materials and furniture.

Need some rooftop inspiration? Check out the design of this rooftop by SJB and William Dangar here

2. Take into account the elements

Cleveland Rooftop by SJB & William Dangar | Image: Felix Forest
Cleveland Rooftop by SJB & William Dangar | Image: Felix Forest

Rooftops are typically exposed sites that have to deal with all the elements. They can get very hot during the day, particularly throughout summer. Besides the sun, ambient heat will warm up the space from the reflection of the roof surface and surrounding structures. If unsheltered, your rooftop will also be exposed to high winds.

Protecting your plants will be key to the success of your rooftop garden. It’s best to plant drought-tolerant varieties, especially in areas which are exposed and shade-tolerant varieties in the areas which are heavily shaded from surrounding buildings. Hardy plants such as sedum sp, Pig face Carpobrotus glaucescens, olives, agave and native tussock grasses all fare well up on a rooftop.

When dealing with wind, you’ll want to use heavy pots and containers that won’t take off or topple over on those windy days. The same can be said for furniture. Plastic, light-weight chairs and tables are not ideal in this setting. Opt for heavier pieces that will also withstand the harsh environment.

3. Think about your materials

Redfern rooftop by Adam Robinson Design | Image: Natalie Hunfalvay
Redfern rooftop by Adam Robinson Design | Image: Natalie Hunfalvay

Considering the durability of your materials is very important when creating a rooftop garden. Afterall, you’ve gone through the effort and costs of getting the materials up to your rooftop, it would be a shame to have to replace them a few years after they’ve been installed.

Materials such as natural stone offer the level of durability you’ll want for this space. There are also many options such as Lichen® Split Stone as seen here in this rooftop by Adam Robinson that will help minimise the sun glare and disguise any dirt build up. If you are considering natural stone for your rooftop surface, just remember you’ll need to factor in the weight.  Where load bearing is an issue, timber decking may be a good alternative.

You can read about the pros and cons of stone paving vs timber decking here. 

4. Consider water and drainage

When planning your rooftop space, consider the practicality of watering your garden. During the summer, you’ll most likely need to water your garden at least once a day. Running a hose up to the roof is impractical as is walking up and down stairs with a watering can. Consider installing drip irrigation system on a timer.

Drainage is also a key component of a successful rooftop. It’s important to figure out the waterproofing to avoid damaging the surface below and drainage before you start planting. Not only will plants require well-drained soil, especially during periods of increased rainfall, you’ll also need to consider how this water is drained from the roof itself.

5. Inject some personality

Cleveland Rooftop by SJB & William Dangar | Image: Felix Forest
Cleveland Rooftop by SJB & William Dangar | Image: Felix Forest

Rooftops are the ideal space to have a little fun and inject some personality. Consider how you want to use the space. Do you want it as a place to entertain a crowd outdoors? Is it a space for growing produce?  Is it an extension of your interior living space?

Have a little fun with the space like  SJB and  William Dangar have in this rooftop garden by installing an outdoor bath and a large pond. Several art pieces also add to the personality of the rooftop.

See more of this rooftop by SJB and William Dangar here