Rooftops Gardens

Boy, do They leak!

Let’s talk rooftop gardens.

At Danrae Group, we provide high-quality, compliant and comprehensive waterproofing solutions across commercial, civil, construction, government and strata sectors.

As experts in end-to-end waterproofing solutions, we know that effective waterproofing requires a holistic approach. This means that we may waterproof several areas of a property, including basements, lift shafts, balconies – and rooftop gardens.

Also called green roofs, rooftop gardens are becoming increasingly popular in strata and commercial spaces due to their environmental, aesthetic and wellbeing benefits. They require a slightly different approach to standard flat roof waterproofing, with some key considerations.

About the gardens.

Green roofs can be created on pitched or flat roofs, with the surface partially or wholly filled with soil and vegetation that grows above a waterproofing membrane.

A green roof consists of several layers. Vegetation sits above a substrate layer, which contains drainage and landscaping materials. And beneath this is the protective waterproofing membrane. The membrane acts as a barrier to water seepage from both environment and the garden.

The Australian Government’s Your Home guide to sustainable homes lists several benefits of green roofs, including improved sound, heat and cooling insulation, increased biodiversity, reduced and slowed stormwater runoff, the capture of pollutants, and a longer roof lifespan.

Types of gardens.

While the definitions are not rigid, green roofs are usually classified as intensive or extensive. Typically, extensive green roofs are shallower gardens with less than 200mm of soil and ground cover vegetation. This type can be retrofitted to existing buildings, be low maintenance and is relatively economical. Still, as they only support weights of between 60–200kg/m2, they are not suitable for people to access.

Intensive gardens can hold soil up to 1m deep and support vegetation up to tree size and many plantings.

Intensive gardens support much greater loads – between 180–500kg/m2 or more – so they are suitable for access.

Intensive green roofs are more expensive given structural requirements, but they also have greater thermal and acoustic properties. Intensive rooftop gardens generally include additional seating, paved areas and decking.

Membrane consideration

The Danrae Group team is certified and experienced working with all membrane varieties, so we understand the best options for diverse applications.

Rooftop gardens require a membrane that will support the garden weight, be robust enough to resist gardening chemicals, withstand diverse weather conditions and damp soil and be flexible in responding to structural movement.

Given vegetation roots can cause significant damage to unsuitable membranes, it’s essential that the membrane also be root-resistant. In a recent blog on new waterproofing technology, we featured Ardex Root Repell™, a great product with a plant root repellent impregnated within the membrane. It works to repel roots away from the membrane without killing them, so it’s a good option for both rooftop gardens and planter boxes.

Managing your rooftop garden.

At Danrae Group, our comprehensive waterproofing solutions include diagnostic, solution design, remediation, waterproofing and preventative maintenance. And we can onboard for new construction or existing rooftop gardens.

If you leak a rooftop garden, we use various testing techniques and technology to pinpoint the exact location. With multiple trades skills in-house, including building, carpentry and tiling, we look after every stage of roof remediation, including site preparation and induction, rebuild and clean up.

And our complete project management covers every aspect of a project, including crane hire, council permits and tenant communication.

You Can Trust Danrae.

At Danrae Group, we provide end-to-end project management and comprehensive leak detection, solution design, waterproofing and remediation from our skilled in-house team of waterproofing contractors and trades professionals.

Our team tailors every solution design to the type and location of the property, we triple test every waterproofing installation, and we provide a full waterproofing guarantee. We also offer preventative maintenance plans to preserve your waterproofing solution and the integrity and value of your property.

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Please feel free to call Danrae Group on 1800 326 723 to discuss your needs.

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