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1. ROOF GARDENS
Building Material and Construction- IV
By: Zeeshan Asim

2. INTRODUCTION
A roof garden is any garden on the roof or any
floor of the building.
Besides the decorative benefit, roof plantings may
provide food, temperature control, hydrological
benefits.
Also provides architectural enhancement, habitats
or corridors for wildlife, recreational opportunities,
and in large scale it may even have ecological
benefits.

3. Why A Rooftop Garden?
• Reduce the “urban heat island
effect”
• Reduce amount of greenhouse
gas
• Provide more space
for agriculture
• Reduce and clean storm water
runoff
• Reduce energy consumption
• Increase the beauty
of cities

4. ROOF CONSTRUCTION
• Can be constructed from wood, metal, concrete, plastic,
gypsum, or composite
• Concrete decking will provide the most sturdy roof
structure

5. SHALLOW ( ULTRA
EXTENSIVE)
•Shallow Roof Garden System (growth
media depth 2.5” to 4") is ideally
suited for areas likely to receive little
maintenance.
•Recommended plants include sedums,
herbs and grasses.
TYPES OF ROOF GARDEN
The anticipated weight above the membrane assembly is generally between
4.8 and 6 pounds per square foot.

6. • Medium Depth Roof Garden System
(growth media depth of 5" to 8") includes
plants such as sedums, herbs, grasses and
other vegetation, which can grow in this
depth of media.
• Spray irrigation systems may be required
to support more diverse plant types or for
installations in semi-arid climates.
• The anticipated saturated weight above the
membrane assembly is less than 50
pounds per square foot.
Medium Depth (Extensive) Roof Garden System

8. Extensive Roof Garden

9. • Deep Roof Gardens typically incorporate a planting
system requiring greater growth media depth
(exceeding 8") that requires regular maintenance,
such as watering and fertilizing.
• A variety of plants are
available including turf grass, flowers, shrubs and
even small trees.
• This system typically requires a structural concrete
roof deck to support the larger dead load.
• An irrigation system should be utilized
in these assemblies.
• The anticipated weight above the membrane
assembly is generally greater than 50 pounds per
square foot.
Deep (Intensive) Roof Garden System

11. Constraints of a Rooftop garden
• Condition of the roof
• Structural capacity of the roof
• Access to the roof
• Cost
• Irrigation
• Drainage

12. LAYERS OF A GREEN ROOF
• Vegetation
• Growing medium
• Filtration membrane
• Drainage layer
• Protection & storage layer
• Water proofing membrane
• Roof construction

14. Calculate amount of weight roof can support. The weight of
soil, decking, people and planters - and where they are placed -
will all depend on the load bearing capacity of your roof.
These ideas to reduce the load on your roof:
• Mix soil with organic and inorganic matter to lighten its weight,
or use lightweight growing mediums, such as pre-mixed planting
soils.
•Plan for heavier items to be aligned with the building’s bearing
walls, columns and shear walls, which have the added support of
the footings below.
Loading Capacity

15. Drainage
•Keeping access to the drainage system free and clear is a priority.
•can be done on green roofs by maintaining a gravel ring and filter
cloth layer around roof drains and overflow scuppers.
•On rooftop gardens, ensure that any deck strapping or containers
are aligned in such a way that they don’t block the flow of water to
the drain.
•Watch and determine where water flows to on your roof and ensure
those areas and drainage paths are maintained roof is designed such
to withstand pooling of water.
•An added layer of protection should be provided (a drainage layer)
over the roofing membrane to protect it from standing water that
may collect from watering plants.

16. Maintenance
•To maintain clear access to the roofing membrane and
drains for maintenance and repair, install rooftop garden in
sections. This can easily be done using containers of any
height or size, arranged in sections on roof.
•Designing rooftop garden in sections will avoid removing
the entire garden area each time the roof needs some repair
work.
•Remember to factor in the weight of each container and its
wet soil weight when designing the garden.

17. Choosing plants
•Gardening on a roof is quite different from gardening at ground level.
Rooftops have unique and often extreme microclimates. The amount of
sun and wind roof receives will have a direct effect on what will grow.
•For roof garden consider the amount of time and resources required
for watering and maintaining plants, especially during the summer.
Sun and Wind — The height and location of building in relation to
surrounding buildings can affect the amount of sun rooftop garden
receives, as well as the exposure to wind.
•Determine the wind and sun conditions on roof and select hardy plants
that can flourish under the conditions rooftop garden provides your
roof.

18. Soil depth — Most plants can grow on a roof as long as
they are provided with an adequate amount of soil to
stabilize and flourish. However, soil depth may be a
limiting factor on some roofs. Make sure to study the
depth of soil required for different species of trees,
shrubs and wildflowers so as to match the right species
with the conditions provided.
Availability of water — Watering during the summer
months should be addressed in advance.
• Summer is when the garden and plants need the most
attention.

19. DISADVANTAGES
• Initial cost of installation is high
• Pest insects could easily infiltrate a residential building through open
windows
• For intensive green roofs there is additional cost of reinforcing the building
• Based on the green roof types, the maintenance work and the cost of
installation are high

20. ADVANTAGES
• they filter urban pollution and reduce carbon dioxide
• they cool the air by evapotranspiration of water vapor
• they reduce wind speed
• they promote the settlement of animal ecosystems
• they reduce the transmission of noise inside the building
• they reduce the effects of “urban heat islands”
• they increase the heat resistance of the roof
• they protect the waterproof covering and increase its lifetime
• they are a tool of new architectural expression

21. To overcome the upcoming threats of global warming,
the adoption of green roof technology is a small step to
save our planet.

22. IT’S DONE!