Comparing 2 Technical Reports
Read through the 2 reports below enough to understand them/compare them. then, answer the questions below.
Corporate
Report
Clerk’s Files
Originator’s
Files EC.19.GRE
DATE:
September 28, 2004
TO: Planning and Development Committee
Meeting Date: October 18, 2004
FROM: Edward R. Sajecki
Commissioner of Planning and Building
SUBJECT: Green Roofs
ORIGIN: Planning and Building Department
BACKGROUND: This report is in response to a request from Councillor Mullin’s
office to report to Planning and Development Committee on green
roofs.
COMMENTS: Definition of Green Roofs:
A green roof is a contained green space on top of a human-made
structure and is an extension of the existing roof, not potted plants
(sometimes called roof gardens). Green roofs consist of the
following layers:
• a special water proof and root repellent membrane;
• a drainage system;
• filter cloth;
• a lightweight growing medium (soil); and
• plants.
Planning and Development Committee – 2 – September 28, 2004
Types of Green Roofs:
• intensive, extensive or semi-extensive;
• accessible or inaccessible;
• incorporated into the design of new buildings or added to an
existing roof provided that the structure can accommodate it.
• incorporated into the design of new buildings or added to an
existing roof provided that the structure can accommodate it.
Intensive green roofs have a soil depth of 15 cm (5.9 in.) or more,
usually provide a park-like setting with public access and require
regular maintenance. Extensive green roofs have a soil depth of
less than 15 cm (5.9 in.), are low weight, low cost, require minimal
maintenance and normally are not accessible to the public.
Benefits of Green Roofs – public and private
Ecological Benefits:
• stormwater management – reduce stormwater runoff, improve
stormwater quality and temperature;
• climate moderation – reduce Urban Heat Island Effect;
• improved air quality – absorb heat, filter air, produce oxygen,
reduce smog;
• create wildlife habitat and biodiversity; and
• energy conservation.
Economic Benefits:
• prolonging roof life and offers roof protection;
• energy savings – provides building insulation;
• noise reductio n – sound insulation;
• added property value;
• enhanced corporate image;
• proven return on investment through savings in hearing and
cooling costs, as well as, roof maintenance; and
• create jobs.
Planning and Development Committee – 3 – September 28, 2004
Social Benefits:
• enhance overall quality of life – improve human health and
well-being due to additional oxygen, air filtration, humidity
control, horticultural therapy;
• improve urban aesthetics and provide sense of space – convert
unappealing hard surface roofs into natural landscapes;
• provide additional recreational spaces – parks, nature
preserves, community gardens, social meeting spaces, green
spaces to look upon;
• possibility for urban agricultural – growing food locally; and
• ties into Smart Growth strategies – Healthy Cities, enhances
infill development.
Costs, Payback and Incentives:
Depending on the type of green roof, it may cost twice as much as
a conventional roof. The payback to the building owner results
from reduced energy costs, lower heating and cooling costs and
less maintenance. The overall social benefits are tremendous.
Some governments throughout North America and Europe provide
incentives to promote green roofs on private buildings including:
financial support programs, fee reduction, density bonusing and
zoning.
In Canada, there are government programs available for research
and promotion of green roofs through: Commercial Building
Incentive Program, Industrial Building Incentive Program, Green
Municipal Enabling Fund and EcoAction.
Building Code:
The Ontario Building Code does not address green roofs
specifically. However, the Building Code does require that the
design of the structure be able to accommodate the load of the
additional layers and that drainage be adequately addressed.
Planning and Development Committee – 4 – September 28, 2004
Municipal Examples:
For centuries, roofs have been used for growing plants, but the
emergence of a green roof industry is fairly recent. Green roofs
have been popular in Europe for over 40 years, however, in North
America it is a relatively new concept. The vast majority of green
roofs are found on government and institutional buildings, but
there are also many examples on private buildings. Many cities in
North America have demonstration sites for green roofs and have
policies and incentive programs in place encouraging green roofs.
In the United States, cities such as Chicago, Portland, New York,
Dearborn and Seattle have city ordinances and have green roofs on
some municipal buildings. In Canada, cities such as Toronto,
Waterloo, Vancouver, Kitchener, Guelph and Winnipeg have
demonstration green roofs.
The City of Toronto supports and encourages green roofs in their
Official Plan. Under their Natural Environment section of the
Official Plan, policy #17 states: “Innovative energy producing
options, green industry and green building designs and
construction practices will be supported and encouraged in
building renovation and redevelopment through: f) the
development of innovative green spaces such as green roofs, and
designs that will reduce the urban heat island effect.” Other
examples encouraged by the policy relate to: reduction of
stormwater flows, water conservation and efficiency, waste
reduction and recycling, renewable energy systems and advanced
energy-efficient technologies.
In addition, the City of Toronto has two committees dedicated to
environmental issues. One is the Round Table on the
Environment, which is an advisory committee, and the other is an
Interdepartmental Task Force, which coordinates common
interests, both of which, amongst other environmental issues, deals
with green roofs.
Planning and Development Committee – 5 – September 28, 2004
Research:
There are several research projects underway in Canada regarding
green roofs. Various stakeholders provide funding and in-kind
support for these projects, such as:
• Canada Mortgage and Housing Corporation
• Environment Canada
• National Research Council Canada
• Ministry of Environment
• Toronto and Region Conservation Authority
• Canadian Federation of Municipalities
• Ontario Power Generation
• universities and colleges
• municipalities
• Green Roofs for Healthy Cities
• private sector
Toronto has received funding through the Green Municipal
Enabling Funds to explore the feasibility of green roofs in the City
of Toronto, namely: what are the real benefits to the City;
cost/benefit analysis; and investing in green roofs through grants,
fees, etc. The study will serve as a template to other municipalities
to assess the benefits of green roofs. The results of the study are
anticipated to be released in the spring of 2005.
The City of Waterloo is presently conducting a green roofs
feasibility study to evaluate a number of municipally-owned
properties for their suitability for a green roof.
Environment Canada is doing a project to model the urban heat
island effect in Toronto. Included in the model is green roof
technology.
Green Roofs for Healthy Cities is a network of public and private
organizations whose mission is “to develop a multi – million dollar
market for green roof infrastructure products and services in cities
across North America in order to take full advantage of the
multiple benefits of these proven technologies”. They are
conducting a study in Toronto to determine the viability of
different plant species and a range of extensive and intensive
Planning and Development Committee – 6 – September 28, 2004
applications in the Canadian climate. They are also monitoring the
stormwater runoff from the Eastview Community Centre green
roof in Toronto to assess the effectiveness of green roofs as a
stormwater management option.
Food Share Toronto is exploring the design of rooftop growing
systems for commercial food production.
The Rooftop Garden Consortium in Ottawa is researching the
benefits and durability of rooftop garden technology in Canadian
climates and sensitivities to climate variability. They are
developing a model to predict the performance and benefits of
green roofs in different Canadian cities.
Greenroof Systems Consortium is a public-private sector
partnership whose members include Toronto and Region
Conservation Authority, Seneca College, York University,
Greenland International Consulting Inc. and Sustainable
Development and Monitoring Inc. They have a project underway
which will showcase new and existing technologies for the purpose
of promoting sustainable development in Southern Ontario and
elsewhere.
Staff could arrange a presentation at Planning and Development
Committee on the status of the research, if required.
CONCLUSION: Green roof technology is one aspect of green building design
which provides benefits to air quality, stormwater management,
health and well being, climate moderation, wildlife habitat and
energy conservation. Many municipalities in North America have
demonstration sites on municipally owned buildings and promote
green roof technology in building design. There is considerable
research underway which is exploring the feasibility of green roof
technology in Southern Ontario.
Planning and Development Committee – 7 – September 28, 2004
RECOMMENDATION: That the report titled “Green Roofs”, dated September 28, 2004,
from the Commissioner of Planning and Building, be received for
information and further that staff monitor the research on green
roof technology and report to Planning and Development
Committee on a regular basis.
Original Signed By:
Edward R. Sajecki
Commissioner of Planning and Building
k:\…\policy \…2004 Envir\Special Projects \Green Roofs Report
Felton Properties Green Roof Report
400 SW 6th Ave Portland, OR
400 Building
Introduction:
The ecoRoof will combine innovation with practicality. The building is
currently seeking LEED Gold certification, and ecoREAL will work in an
integrated fashion with roofing experts specializing in weatherproofing,
structural engineers and green roof companies specialized in the bio-
regions native plant species to come up with the best design and function
for meeting the building overall green building goals. Water drainage,
low-impact design and aesthetic will be looked at simultaneously. At
each layer of the green roof sustainable design attributes will be assessed
for regional material (especially vegetation) and recycled content (such
as the HDPE geo-cells) in the drainage system along with triple bottom line
life-cycle assessments on how the project affects the context (such as
HVAC systems, and surrounding buildings). Since the building is on a zero-
lot, the green roof grant is critical for pursuing LEED certification relating to
both Sustainable Sites and Water Efficiency credits. The green roof would
augment Felton Properties commitment to retrofitting their existing
building stock to be more sustainable.
Left: Looking South over green roof installation
Right: Looking Northeast over green roof installation
Project Type Commercial retrofit
Technologies
Malarkey roofing tray system 2000 sqft
Tuff Stuff – Sedum Tile
Major Benefits
Stormwater management – limit disruption and pollution of
natural water flows by managing stormwater runoff.
Heat Island Reduction – reduce heat islands to minimize impact
on microclimate and human and wildlife habitat.
Cost $70,192.00
Constructed
.O. Box 17217, Portland, OR 97217-0217
Telephone: (503) 283-1 www.MalarkeyRoofing.com
.O. Box 17217, Portland, OR 97217-0217
Telephone: (503) 283-1 www.MalarkeyRoofing.com
System Components: AVRS Tray System
System Components: Tuff Stuff – Sedum Tile
Technical Data
Vegetation – 95% coverage
Fiber/Soil Base – Approx. 1” thick
Measurements – 15”w x 20”l x 2”-3”h
Area = 2.08 sqft per tile
Max weight – 4.5 #/sqft fully saturated
Irrigation:
No irrigation was used on this project. The tray system chosen was
designed and planted to not utilize any irrigation system.
Budget:
Existing Roof make minor tune up repairs
At window washer davits and supports, clean and reseal all with SBS
modified mastic and with granules
Make misc. minor repairs and reseal all pipe penetrations
At west parapet reseal parapet cap metal flashing joints
Total: $9,900.00
Green roof option 10% of total roof area 2000sqft
Install 1/8 inch protection board underneath green roof trays, 2000sqft
Install Malakey roofing tray system with fully mature plants, 2000sqft
Provide crane service to load green roof trays to roof at SW side of
building ($9,211.00)
Total: $60,292.00
Success and Lessons Learned:
In beginning our search, it was important to find a green roofing option
that required little maintenance. We were successful in finding the perfect
selection after a little research. By choosing a drought resistant choice,
the maintenance requirements change drastically. Doing our research
ahead of time helped tremendously in terms of setting goals, but having a
seamlessly coordinated team from the beginning would have helped. In
the future we realize the importance of connecting the roofing contractor
with the green roof manufacturer and the nursery providing the
vegetation, in order to make sure all of the project goals are met with few
setbacks and no change orders.
400 Rooftop plan showing dimensioned green roof.