Rooftops could easily be turned into valuable green spaces.
Green roofs can be divided into two types: the vegetation-covered or “inaccessible roof” where the soil and plants form another layer of the roofing system, and the rooftop garden, or “accessible” roof that can become an outdoor space.
PHOTO Courtesy of Aloe- Aloe - Sunbird Aloes ‘Southern Cross’
Green roofs and rooftop gardens can provide many benefits,
including:
Increased access to safe outdoor green space;
Reducing sound reflection and transmission;
Promotion of individual, community, and cultural diversity;
Areas for study and horticultural therapy;
Improved air quality and absorption of carbon dioxide;
Minimization of stormwater run-off, and support for a rainwater collection system;
Increased habitat for birds, butterflies, and insects; and
Reduced heating and cooling costs by providing a layer of insulation on buildings.
Reduces the spread of wildfires.
Cross-Section of a Green Roof
Starting from the bottom:
1. Roofing membrane;
2. A layer of filter cloth to prevent the roots from penetrating the roofing membrane;
3. A drainage course of gravel or expanded clay pellets;
4. A layer of filter cloth to prevent soil, growing medium, or organic matter from eroding
or clogging the drains;
5. Growing medium; and
6. Plants
Cross section of possible green roofs (by Eva Drukker)
Flat roofs as opposed to angled roofs are best used for rooftop gardens. Flat roofs can offer a depth, of 6 – 12 inches of growing medium depth. Always consult your engineer or architect-engineer to properly determine how much weight your roof can hold, and how that weight should be dispersed on your roof.
Key Things to Consider in the Design of Your Rooftop Garden
1. Calculate the loading capacity of your roof.
2. Plan for drainage from rainfall and from watering plants.
3. Plan for access to the roof membrane for maintenance and repair.
4. Choose the right plants for your rooftop garden.
5. Incorporate built features in your garden to suit your goals.
Sunbird Aloes are a popular choice for the green roof, because of their flower performance, their ability to grow in the shallow medium, and their easy-to-care-for and low water use qualities.
Small to Medium-sized aloes have shallow roots and can tolerate times of drought and high precipitation, as well as intense heat, high winds, and possible pollution.
Also tolerant of sea spray and wind for coastal gardens.
PHOTO Courtesy of Aloe-Aloe – Sunbird Aloes ‘Topaz’.
For more information on the small and medium size aloes, you could use in your rooftop garden: www.ndundulualoes.com. The Sunbird Aloes are placed into their flowering times of the year. Allowing you to enjoy a longer flowering period.
References;
Evergreen; gardening techniques
noldus. com-roofs-research-biodiversity
Aloe-Aloes - Sunbird Aloes
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