New York Highline – one of the World’s best known Roof Gardens

A Roof Top Garden is a great way to escape the hustle of the streets below. As more people are choosing to live in apartments, roof top gardens are becoming a necessity to our urban environment as they cool the building and reduce your energy costs. The plants also remove carbon dioxide from the air and replace it with more breathable oxygen.

How often have you noticed a fabulous roof top garden and said, ‘that looks great, I want to do that on my roof’. More…

The two things that you need to ask yourself are, what am I allowed to put on the roof, and how do I want to use my roof top garden? For a new building, the infrastructure for a roof top garden was probably incorporated into the architectural specifications from the get go.

For an existing building the very first thing to know is the structural limitations of the roof top. If your planning on placing a limited number of trees and shrubs in pots across your section of the roof, and it has already been done elsewhere on the roof, it is likely the structure will be ok.

If your building is part of a Strata Plan, the Strata Manager will need to approve your proposal, with particular reference to the load bearing capacity of the roof. He or she will advise if a Structural Engineer’s Report will be necessary. The Strata Manager may also want to know about water proofing and drainage, and the appearance of the garden from the street (if visible).

I once made the mistake of accepting the verbal advice from a Building Manager, who told me categorically that the structure would support the weight of a swimming pool. I spent a lot of time going nowhere because he was wrong. So now I always obtain a copy of a Structural Engineer’s Report early in the process.

Depending on the circumstances, you may also need the approval of the local Council. The Council will not process an application unless the Strata Manager has given prior approval. The Council will similarly want to know about various aspects of your proposal, as well as the the specifications of the perimeter balustrade. It must be at least one metre above the roof surface and constructed in a way that prohibits climbing on and over.

The planning of a roof top garden is more rewarding when you have an idea of all that is permissible, and then you can budget responsibly.

If you plan to entertain friends on your roof top garden, you will need to appreciate the implications of different weather conditions that exist on a roof top. Furniture will need to be solid enough not to move in the wind, be UV resistant and not restrict that fabulous view.

Growing trees in strategic locations will enhance the entertainment area with shade, and reduce the temperature in the immediate vicinity.

If you want to grow a herb garden, you will need to ensure there is adequate water supply, good drainage and protection from stronger winds. Being aware of the various growing mediums (ie soil alternatives) is invaluable to the success of your herb garden.

The right choice of plants is vital, and an onsite visit by a professional Landscape Designer will enable him or her to give the right advice towards creating a very sustainable and enjoyable roof top garden.