1. Insulates
buildings,
therefore
conserving
energy.
Improve air
quality and
reduce CO2
emissions.
Absorb and retain
rain fall, reducing
and delaying
stormwater
system load.
Reduce ‘urban
heat island
effect,’ where
solar energy
is re-radiated
off buildings,
heating the
surroundings.
Increase access
to private outdoor
green space within
the urban
environment, at
home or at work.
Promote
individual,
community,
and cultural
diversity.
Any roof surface
can be greened
- even sloped
or curved roofs
can support a
layer of sod or
wildflowers.
Water proof
membrane is
fundamental basis
of all roof top
gardens. To limit
leakage problems:
Compartmentalise
planting beds, or
use moveable
containers.
Protect membrane
from shovels, heels
etc with a pebble
drainage layer, and
use raised walkways.
Keep garden free
draining. Include
filters and drain
covers in
this system.
Keep compost in
own container for
turning, aeration
and leachate
collection.
Legislation
for urban
green roof
tops is
appearing
globally.
Rooftop
gardening is
fashionable!
A new category
in the Chealsea
Flower Show
illustrates the
growing
popularity.
Low growing,
drought
tolerant
systems can
require no
maintenance.
Improve
urban
aesthetics
Increase
the value of
buildings for
owners and
tenants.
Create job
opportunities in
the fields of
research,
design,
construction,
landscaping,
gardening,
health, and food
production .
Use unused
space for
productive
purposes.
Rising
populations
rely on
shrinking
farmlands.
Increase
habitat for
birds.
Support
urban food
production.
Give a little
something
back to the
world!
Reconnect
with the
cycles that
support our
lives.
Consider all Factors Analysis 1

2. Consider all Factors Analysis 2
Access can be a
problem for set
up. All soil etc
may need to be
brought up to
the roof in bags,
using stairs or
the elevator.
If a building is to
be retrofitted
with a green
roof, a structural
engineer
must be
consulted.
Odours from sewer
vent pressure
pipes and grease
vent pipes on roofs
require scrubbers
to be fitted.
Composting could
bring about smell
or vermin if
practised poorly.
Warning:
gardening
may be
addictive.
Where rooftop
gardens have
not yet been
officially
recognised in
building codes,
the safety of
such projects
is left to the
discretion of
individual
building
inspectors.
Terra-cotta
containers
usually crack
in hard frost
conditions.
Plant
selection is
often
restricted
by arid and
exposed
roof top
environment.
www:
.cityfarmer.org
.rooftopgarden.com
.egov.cityofchicago.org
.asla.org/greenroofeducation
.thegreenroofcentre.co.uk
.bonnieplants.com
.lifecyclesproject.ca
Hydroponic systems,
and highly modified
eco systems, may
become more
dependant on
chemical inputs.
Initial
installation
costs can
be high.
Depending on
greenroof type,
maintenance can
be just as great
as a normal
garden.
Ownership issues
may arise between
tenants and
building owners.
Container
gardening is a
different experience
from traditional
gardening, and
new skills will have
to be learned.
Lack of
information
and expertise.
Shallow beds or
pots require con-
sistent and regular
irrigation; at least
once par day in
summer.
Gardeners in
high-rises have
great intentions to
water once a day,
but they don’t!
Drip irrigation
may be required.
More extreme
growing
environment,
especially sun
and drying
Use and
productivity
may be highly
seasonal.
Limited availability
and selection in
some city areas for
soils, composts,
plants.