The document discusses green roofs and their implementation in Erbil City. It provides background on green roofs, their history and types. The document finds that Erbil has a low percentage of green areas at 6.5% compared to an international standard of 30%. It recommends implementing extensive and semi-intensive green roofs on individual building projects in Erbil to increase green space. On a city scale, the document suggests leaders support green roof laws and increase public awareness of their environmental benefits.

1. Green Roofs and Their Implementations in Architecture
The obstacle and challenges in Erbil city
Siba Nadhim Kady
Sahar Mohammed Yahya

2.  In the last five years, the term green roof has taken on
ecological and social significance beyond its seemingly
simplistic description, this term has become an epithet for the
reduction of pollution and improving urban environment.
 Green roofs infrastructure promises to become an increasingly
important solution for building owners and community
planners which provides a significant numbers of social,
environmental and economic benefits that are both public
and private nature
 interestingly recent statistics suggested that the percentage of
green areas in Erbil the capital city of Kurdistan region is
approximately 6.5%, while according to international
standards 30% of urban areas should be green.
Abstract

3. Research problem
the ambiguity of green roofs implementation
techniques in the region.
the goal is initiated to determine the obstacle and
challenges of green roofs implementations in Erbil city
as case field by analyzing international experiences
and concluding Erbil’s green roofs criteria
Research goal

4. Introduction
 Erbil city is facing environmental problems such as waste
water treatment, water supply, land preservation, air
and noise pollution, although few parks have been
constructed during the past few years, the focus has
been on the main streets and less in residential areas
 Moreover, in Kurdistan, people lack the awareness that
planting trees is beneficial for the atmosphere and can
lead to a better living environment for them and their
children. Ironically, not only do some people not plant
trees, they sometimes uproot or cut trees planted by the
government

5.  Climate changes, increasing temperatures, storms
and flooding’s especially in the our region, it is not a
forecast, it is happening now. for example Syria has
had its fourth consecutive summer of droughts while
Yemen is struggling with what is considered its worst
flooding in a decade, morocco also affected by
frequent drought, also the country now, Erbil
included, experiences five or six droughts every
year.
 Without a national campaign by the people and
the government for increasing greenery areas and
promoting nature, there is a little hope for the future

6. Green Roofs History
 Green roofs date back to thousands of years. The oldest green roof appears
to be the ziggurat of ancient Mesopotamia, built from the fourth
millennium until 600 B.C.E.
 During the middle ages and renaissance, roof gardens were owned by the
rich and monks.
 Germany is known as the birthplace for modern day green roof systems.
 In the modern time there were two advocates of green roof technology the
architects Le Corbusier and Frank Lloyd Wright. Although Le Corbusier
encouraged rooftops as another location for urban green space, and Wright
used green roofs as a tool to integrate his buildings more closely with the
landscape, neither was aware of the profound environmental and economic
impact that this technology could have on the urban landscape
 Green roofs now are the new trend of aesthetical, environmental, economic
and above all sustainable solution for urban environmental problems

7. Green Roof definition
green roofs are mainly the covering for any built
structure at any elevation such as a parking structure,
academic or assembly facility, or any commercial or
residential structure-and thought of as being
programmed and designed for supporting a layer of
vegetation to mitigate storm water loss and heat gain
or as usable, comfortable open space that helps to
improve urban environments.

8. Green Roof Types: A Comparative Review

9. Extensive Semi intensive Intensive
Maintenance Low Periodically High
Plant Communities Ground covers,
grasses
Ground covers, grasses and
shrubs
Lawn or shrub and trees
Plant types Grasses and loans,
ground covers,
seasonal flowers
Climbers, cactus and
succulents, shrubs
Palm trees, ornamental trees,
aqueous plants
Plant Diversity low plant diversity More plant diversity high plant diversity
System Built Up
Height
150- 250 mm
Thin growing medium
250- 500 mm 250- 500 mm, provide planters
for trees and palm 1000mmm
Deep soil
Weight
approximate
50-150 kg/m2 <150 kg/m² >150 kg/m²
Cost Low Medium High
Use Ecological protection
layer
Designed green roof Park like garden, designed more
for aesthetics than performance
Accessibility Not Semi accessible accessible
Irrigation
Requirements
little or no irrigation little irrigation irrigation system; more favorable
conditions for plants

10. Extensive Semi intensive Intensive
Benefits
• Lightweight; roof generally does not
require reinforcement
• Suitable for large areas.
• Suitable for roofs with 0 - 30° (slope).
• Low maintenance and long life.
• Often no need for irrigation and
specialized drainage systems.
• Less technical expertise needed.
• Often suitable for retrofit projects.
• Can leave vegetation to grow
spontaneously.
• Relatively inexpensive.
• Looks more natural.
• Easier for planning authority to demand
as a condition of planning approvals.
• Greater diversity of plants
and habitats.
• Good insulation properties
• More energy efficiency and
storm water retention
capability
• Longer membrane life
• Longer membrane life
 Greater diversity of
plants and habitats.
 Good insulation
properties.
 Can simulate a wildlife
garden on the ground.
 Can be made very
attractive visually.
 Often accessible, with
more diverse utilization
of the roof. I.e. for
recreation, growing food,
as open space.
 More energy efficiency
and storm water retention
capability.
 Longer membrane life
Downsides
• Less energy efficiency and storm water
retention benefits.
• More limited choice of plants.
• Usually no access for recreation or other
uses.
• Unattractive to some, especially in winter
• Greater weight loading on
roof than extensive
• Higher maintenance costs
• Greater weight loading on
roof.
• Need for irrigation and
drainage systems requiring
energy, water, materials.
• Higher capital &
maintenance costs.
• More complex systems and
expertise

11. green roof benefits in different climatic
conditions, a comparative review
Climate benefits
Warm Climates -Shading the rooftop layer
-reduction of the direct influence of solar radiations
-reduction of indoor temperature fluctuations
-reduction of indoor air temperature peaks
-reduction of energy used for cooling purpose
Warm And Humid Climate -Indoor daily temperature swings depend on the soil depths
Warm And Dry Climate -Reduction of the outdoor air temperature
-cooling the indoor ambient temperature
Cold Climates -Reduction of daily -temperature swing , reduction of the heat
flow
-doubtful energy performance in winter
-spring and falls, evaporative cooling in the shoulder seasons
may lead to increased building heating loads

12. Green Roof Technical Guidelines
 Roof Conditions and Suitability for Greening
Roof conditions and suitability for greening
function Location Accessibility Climate Wind
the primary
functions a
specific
green roof is
required to
perform, will
have
profound
effect on its
overall
design
The height of
the roof, its
orientation, its
exposure to
wind, sun and
shading by
surrounding
buildings will
have impact
Access to the
green roof site
is vital for the
installation,
ongoing
maintenance
and bringing
up materials.
The general
climate as hot,
humid or cold,
dry should be
considered on
plants
selection.
Wind can generate
positive and
negative pressure
forces, which act
on structures. the
most affected areas
by the wind
pressure are:
 Corners where
stress level are
very high
 Edges, where
stress levels are
high

13.  Green Roofs Components

15.  Structure and bedding stability
Structure and bedding stability
Structure and
design loads
green roof is part of the initial design of the building
Depth and
Weight of
media layers
The depth of media layers range between 2.5c.m-200c.m and the
weight of every layer in a green roof system is determined at the point
of maximum water capacity including materials and stored water.
Roof Slope Intensive green roofs are executed on slopes of up to 5 degrees, while
extensive green roofs on slopes of up to 30 degrees and the maximum
slope is 45 degrees.
Water
Proofing roof
membrane
For an existing building, the membrane should be carefully inspected to
determine if it needs to be repaired or placed before the installation.
Parapet
Design and
Protection
against falls
A lower parapet design in low rise building may avoid potential air
turbulence and help minimize uplift forces, on the other hand high rise
buildings are exposed to increased wind pressure resulting in higher
positive uplift forces.
Fire
Resistance
The integration of fire breaks in all types of green roofs is recommended.
Certain plants should be avoided from use on rooftops that are highly
flammable, or that develop large root systems and thus high biomass, or
that are excessively thirsty.

16. Green Roofs Implementation Levels
 There are two main levels for green roofs implementations, city
scale level and project scale level.
 By implementing green roofs on city scale level, the benefits will be
public for the total urban environment, this level need a lot of
support and previous planning from different institutions whether
it’s on the leaders, legislators, regulators, planners, designers,
builders, and master planning levels.
 On the other hand by implementing green roof on project scale
level, the benefits will be private for building owners and planners.
This level required several procedures like merging landscape and
architecture, enhancing urban microclimate, enhancing the
integration of parking, surface, structured, and underground parking

17. Green Roofs samples
Mountain equipment coop, Toronto, Ontario, Canada [2]
Implementations Level project scale level
Green Roof Type extensive
Overview: This inaccessible green roof garden located on downtown Toronto corporate
Headquarters of the mountain equipment co-op. The 903 m2 green roof area
Surrounds a skylight located on the second floor of the building. The roof has Full
sun exposure and a load capacity of 40 psf. The vegetation is a wild flower
meadow mix of sun flower seeds and perennial plants.
Owner: Mountain equipment co-op
Construction: Installation of the green roof took place in May 1998 and the building Was
constructed during fall 1997- winter 1998.
Drivers: Some items in the program had no quantifiable economic benefit, but to the
owner they contributed to social and community leadership. The building was
intended to encourage discussion and debate about environmental Issues and
the green roof has contributed to this.
Obstacles: The possibilities of added costs of structural redesign allowing for employee
accessibility were barriers. Since the roof structure would have had to be further
upgraded to accommodate live loads, accessibility was not incorporated Into the
design.
Benefits: The green roof does have environmental and community benefits. It will also have
some operating cost benefit due to thermal inertia of mass of growing medium
successful in the establishment of the vegetation and wildlife

18. Vancouver Public Library, British Columbia, Canada [11]
Implementations Level project scale level
Green Roof Type extensive
Overview: This extensive 2 400 m2 green roof in Vancouver can be viewed from surrounding
downtown office towers. The inaccessible roof is located on top the 7 story library.
It is oriented toward the city and the harbor. Four different types of trees, green
and blue/green tufted fescues are planted in a light weight growing medium
which is composed of reconstituted vegetable waste, sand and pumice.
Owner: City of Vancouver
Construction: Building and green roof were constructed in 1995
Drivers: Environmental and aesthetic purposes
Obstacles: None
Benefits: The green roof was a great success
but no quantifiable data collected

19. Vancouver Public Library, British Columbia, Canada [2]
Implementations Level city scale level
Green Roof Type semi-extensive
Overview: This demonstration project is located on the first floor podium roof of the Toronto City
Hall building at 100 Queen Street West. The green roof is accessible to the public. It
features eight different plots that represent a variety of green roof applications. The
eight plots include:
• 2 semi-extensive systems demonstrating a variety of plant types and landscaping
techniques
• Reproduction of the now rare black oak savannah prairie ecosystem type with
native plants drawn from nearby High Par
• A bird and butterfly garden with a mixture of native and non-native material
• 2 extensive green roof plots demonstrating a wide variety of plants
• 2 urban agricultural plots, one of which demonstrates some of the principles and
plant types associated with permaculture
Owner: The City of Toronto
Construction: Re-roofing and green roof were constructed in the fall of 2000
Drivers: Need for Technical research on performance and demonstration
Obstacles: Many constituencies were involved and needed to be accommodated in order to
implement the green roof.
Benefits: The green roof provides an excellent opportunity for public and professional access
to a variety of different types of applications in one place.

20. Green roof in Erbil/ the obstacles and
possibilities
Erbil, as increasingly growing city , the green roofs
gardens could be implemented in two main levels:
city scale level and project scale level with two types
of green roofs extensive and semi intensive

22. Erbil
Implementations
Level
Project scale level
Roof type Intensive
Overview: This type of a green roof garden can be viewed in newly
planned high rise residential buildings
owner Building residence
Construction: 1. Planting
2. Intensive soil
3. Filter
4. Beodrain
Drivers Economic and environmental purposes for building residence
Obstacles This type of green roof should be considered in the design face
of the building in order to pre-calculate all the necessary
constructional treatment for all the loads and irrigation systems
accompanying with it.
Benefits This green roof garden is an ideal social place for rise building
families cause it is accessible and it is provided with
architecture elements such as walk ways, pavements, water
pools, play area, also it contains a great diversity of plants so it
could be one of an economic solution

23. Recommendation
 Leaders and Planners have to encourage and support these two types of
green roof garden and provide laws and legislation for their implementation
in Erbil.
 Increasingly the awareness of the environmental importance of green roofs
garden as one of the effective ways to increase the green areas in the city.
 It is possible to propose an economic and environment-friendly system for
irrigation with the help of recycled water and solar energy where possible
to reduce the energy consumption needed to irrigate the green roofs.
 In order to have a long lasting environmental improvement in Erbil and the
region in general, Green roof implementation should be considered in the
primary phase of any building or city master plan design, and for every
future expanding.
 Further studies should be considered in this field to support the field of
practice of Green roof.