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TO: |
Mayor and Members of Council |
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FROM: |
Jim Sales, Commissioner of Fire
and Community Services Stuart Taylor, Director, |
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PREPARED BY: |
Mavis
Urquhart, Manager, Environmental Leadership |
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DATE OF MEETING: |
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SUBJECT: |
Green Roof Projects |
RECOMMENDATION:
THAT Markham Staff report, “Green Roof Projects”, dated
AND THAT Town Staff be authorized to retain a
consultant to prepare a Request for Proposal (RFP) and provide technical
assistance for construction of an “extensive” demonstration Green Roof on the 2nd
floor of the Civic Centre (southwest wing) at a cost not to exceed $10,000, as described in this report, to be funded
from the 2005 Asset Management Project Green Roof Phase 1 – Civic Centre Account (#56-5350-6789-005);
AND THAT the 2nd floor of the Civic Centre
(southwest wing) be the preferred option for a Green Roof with funding provided
from 2005 and 2006 Asset Management Projects – Green Roof Civic Centre
(Accounts # 56 5350 6789 005 and 76 5350 7326005);
AND THAT the Green Roof installation on the 2nd
level of the Civic Centre be monitored in consideration of potential future
Green Roof projects, including Centennial Community Centre, the 3rd
level of the Civic Centre and other new facilities;
AND THAT Town Staff retain the consultant
preparing the Master Plan for the Civic Centre (Paul Nodwell) to provide
detailed landscape design drawings and contract administration for:
·
replacement
of interlocking paving stones and the expansion of the existing landscape areas
across the entire front of the Civic Centre building; and,
·
an
“intensive” Green Roof”/demonstration garden at the Civic Centre Great Hall
entrance;
at a cost not to exceed $20,000 (funded
from the 2006 Capital Project for Civic Centre Improvements # 7014);
AND
THAT up to $5,000 from the Markham Environmental Sustainability
Fund (Account #87 2800168) be used as seed money to hold a Green Roof
Symposium in the Town of Markham with the non-profit association, Green Roofs for Healthy Cities, to
advance knowledge about Green Roofs, establish working relationships and
explore grant opportunities for Green Roofs;
AND
FURTHER THAT as part of the RFP process for future Town facilities (new
construction and major renovations) an evaluation of a Green Roof be requested.
PURPOSE:
This
report examines potential Green Roof demonstration projects in the Town of
EXECUTIVE SUMMARY:
In
2005, Markham Council identified $125,000 from the Markham Sustainability Fund
for a Green Roof on the Civic Centre in 2005. An additional $125,000 has been
identified for a Green Roof on the Civic Centre from gas tax funding, for a
total of $250,000. This report examines the options for Green Roof demonstration
projects in the Town of
There
are environmental leadership benefits associated for a Green Roof on the Civic
Centre since this location within Markham Centre on the Town’s administrative
building would promote the Town’s commitment to sustainable development. This
report also identifies, however, that there is limited quantifiable return on
investment for a Green Roof at this location because of the nature of the
existing roofing system (inverted roof). A Green Roof does not have the effect
of extending the roof life cycle of an inverted roof design, as is the case for
a conventional roof design (such as Centennial Community Centre). Appendix 2
provides a comprehensive comparison of Centennial Community Centre and the
Civic Centre as potential retrofit projects.
This
report identifies the 2nd level of the Civic Centre (southwest wing)
as the preferred option and recommends retaining a consultant, at a cost not to
exceed $10,000, to prepare an RFP and provide technical assistance for
installation of an “extensive” green roof this year. Release of an RFP will
ensure new products on the market are considered, the compatibility of the
Green Roof and the existing roof membrane is verified and that there is
experienced technical assistance for the construction phase. The estimated cost
of installation is in the range of $150,000 to $225,000 and there will be
ongoing maintenance costs as well. The RFP should include a requirement that
all proposals submitted for the installation include a projected return on
investment. Should this project be approved, funding would come from the monies
identified for the Civic Centre Green Roof project.
This
report recommends an “intensive” green roof over the parking garage at the
entrance to the Great Hall of the Civic Centre as part of a multi-year
interlocking stone replacement program and that the consultant preparing the
Master Plan for the Civic Centre be retained for a cost up to $20,000 to
undertake this work.
It
also recommends that as part of the RFP process for future Town facilities (new
construction and major renovations), an evaluation of a Green Roof be
requested. The intent of this recommendation is to establish a practice for the
Town to consider the potential for green roof on new municipal projects. The
RFP would also specify that the proposals evaluate the benefits of a Green Roof
installation.
Finally,
it recommends that the Town sponsor a Green Roof symposium with Green Roofs for Healthy Cities which
will require up to $5,000 in seed money from the Markham Environmental
Sustainability Fund.
DISCUSSION:
This
section examines: the types of Green Roofs and benefits generally attributed to
them; preferred locations for a demonstration Green Roof project in the Town;
and, proposes a Green Roof symposium be held at the Town of
Types
of Green Roofs and Their Benefits
Green Roofs can be categorized as “intensive” or
“extensive” based upon system weight:
‘i) “Intensive”
Green Roof systems utilize deep growing mediums capable of supporting a wide
variety of small trees and shrubs. They require a high level of maintenance and
because of the types of plants they support, intensive garden roofs normally
must be incorporated into the original building design due to the structural load
requirement.
ii) “Extensive” Green Roof
systems, in comparison have shallow, lightweight growing mediums, which can
support only small plants such as herbs, grasses and wild flowers. They are
intended to be low maintenance and therefore require plants that are hardy,
draught tolerant and preferable self-generating. Because the structural loading
is lower, many existing buildings can be retrofitted to accommodate extensive
systems.’*
*(National Research Council
The benefits of a Green Roof, as summarized in
Appendix 1 of this report, depend in part on the type and scale of the
installation. Of the many benefits that Green Roofs have, only some have monetary value
that can be quantified, such as reduction in energy consumption, or extending
the life cycle of the roof membrane replacement. Other benefits, such as
aesthetic improvement of the urban landscape, reduction of urban heat island effect
and increased habitat areas are more difficult to quantify. In the case of building
retrofits, such as Centennial Community Centre, or the Civic Centre, the
measurable environmental benefits and quantifiable return on investment are usually
not as great as for new construction and primarily relate to cost deferral
since Green Roofs in these locations may extend the life expectancy of the
roof. Examples of Green Roofs include:
Potential
Green Roof Demonstration Projects
1.
Installation on the
Roof of the Civic Centre
The Civic Centre is considered
a desirable location for a Green Roof demonstration project since it is the
administrative centre of the Town and its location within Markham Centre can set
a leadership standard for the future development of Markham Downtown, which is
premised upon principles of sustainable growth. This location was examined in a feasibility
study in 2003 and re-examined by staff recently as described below:
Background - Feasibility Study 2003 for Green Roof on
the Civic Centre
In October 2003, Council
received a Green Roof Feasibility Study for Markham Civic Centre (see Plan - Appendix
3). The study provided an initial structural capacity and design review of
possible options. Overall, the study assessed:
·
Ability of Civic
Centre to accommodate intensive/extensive green roof - Initial
information from the Feasibility Study indicates that increased structural
capacity would be required on the Civic Centre roof to support an “intensive”
green roof. This would require construction and substantial disruption to the
workplace, as well as significantly higher costs than an “extensive” Green Roof
system. While the southwest wing is suitable for an extensive Green Roof, the
feasibility study identified that the atrium roof, directly next to the
executive lounge terrace and north of the cooling room, has structural metal
decking made for loading snow only and that it should not be used for a Green
Roof.
·
Cost
The Feasibility Study
included green roof concept plans for a green roof for both roof levels (southwest
wing) that included amenities, structures and plantings which required adding
structural capacity to the Civic Centre roof. The cost for that project at that time was
estimated to range from $500,000 to 2 million dollars. Staff recommended a
phased “extensive” Green Roof system on both levels at a cost of $500,000.
·
Projected Return on
Investment was not quantified for the concepts proposed in the Feasibility Study – Since installing
a Green Roof on the Civic Centre would be a retrofit project on an existing
building, the quantifiable return on investment would primarily be from
extending the roof life. The Feasibility Study identified suggestions for
incorporating monitoring equipment to measure temperature and storm water
quality and quantity, however, did not examine the monetary return on
investment. (The potential for return on investment is considered in the
following section).
·
Recommendations of
the 2003 Feasibility Study
The report
recommended that:
·
A detailed roof garden design proceed using this
feasibility study as a starting point taking into account structural
limitations of the building;
·
Cost estimates should be revised based upon detailed
design;
·
Detailed design stage will require further information
respecting loading capacity and issues of access; and,
·
Monitoring program should be implemented to measure
environmental benefits of the roof garden including: storm water runoff
reductions, air quality improvements and temperature moderation.
Current
- Options for a Green Roof on the Civic Centre
More recently staff has re-examined
the potential for an “extensive” Green Roof demonstration project on the Civic Centre
using new pre-designed green roof systems which are less expensive, easier to
install and maintain. These pre-designed systems which are based upon specific
roofing membrane products are best suited for retrofit projects, such as the
Civic Centre and Centennial Community Centre. The estimated cost of a Green
Roof on the Civic Centre (see Roof Plan Appendix 3), is as follows:
|
Location |
Area |
Green
Roof |
Leak
Detection Grid |
Total Cost |
|
2nd
floor Civic Centre
(southwest wing) |
11,000 ft.2 (1020m.2) |
$13-$20/ft.2 (including
material and installation) |
$0.35/ft.2 |
$150,000 to $225,000 (includes ballast
removal) |
|
3rd
floor Civic Centre (southwest wing) |
14,370 ft.2 (1335 m.2) |
$13-$20/ft.2 (including
material and installation) |
$0.35/ft.2 |
$190,000 to $290,000 (includes ballast
removal) |
This proposed estimate would include
no additional amenities or maintenance costs. Maintenance costs would likely be
initially included as part of the warranty, as specified in the RFP, however,
ongoing maintenance requirements and costs would have to be monitored.
While
there are environmental leadership benefits associated with locating a Green
Roof on the Civic Centre there is, however, limited quantifiable return on
investment for a green roof at this location because of the nature of the
existing roof, which is “inverted”. An inverted roof system is constructed so
that the roof membrane lies under thermal insulation and a course of sand and
pavers, or ballast (river rock). In a conventional roof system, like
By
developing the Green Roof on the Civic Centre first, Staff will be able to easily
access the roof to frequently monitor plant growth, maintenance and
installation reliability. The 2nd level is recommended for a green
roof since it will potentially have public access whereas the 3rd level
will not. A Green Roof on the 2nd level would also be visible from
inside of the building which is not the case for the 3rd level. While
a Green Roof membrane was applied in 2003 (at the time of roof replacement) in
sections on the 3rd floor of the Civic Centre at a cost of $8,000,
technology has now advanced such that the membrane is not necessary for some
types of Green Roof installations including the products that Town staff has
been considering for this demonstration project. Installation of the Green Roof
on the Civic Centre could begin in 2006.
Another
option for a Green Roof at the Civic Centre is a “Green Roof”/demonstration
garden is at the Great Hall entrance which is examined later in this report.
2. Installation
on the Roof of the Centennial Community Centre Swimming Pool
Centennial Community Centre
was examined in 2005, as a potential location for an extensive Green Roof
demonstration project (see Plan – Attachment 5). This option is for an
extensive green roof located on the swimming pool roof covering an area of
1000m2 which would be installed 2007, after the building addition is
complete. The tender includes a small area of 70 m2
above the building entranceway which will be developed in mid-2006 with
construction of the Community Centre addition. In the Centennial tender award
report Staff recommended that more research be done to determine whether the
existing roof on Centennial’s Pool is suitable for a extensive Green Roof
installation. Since then, Staff has an opinion from a manufacturer of the green
roof system that their extensive Green Roof will not damage the existing roof.
Furthermore, the manufacturers have stated that their Green Roof installation
will significantly prolong the life of the existing roof potentially resulting
in a return on investment of up to $80,000 (2005 dollars) by skipping one roof
replacement. The estimate for the cost for the installation of an extensive
Green Roof varies between $98,000 and $138,000 with an average price of
$122,000. A leak detection system would add approximately $3,500 to this cost,
bringing the total installation cost to approximately $126,000. This proposed
Green Roof estimate would include no additional amenities or maintenance costs.
Maintenance costs would likely be initially included as part of the warranty,
as specified in the RFP, however, ongoing maintenance requirements and costs
would have to be monitored. No public access would be permitted to the
Centennial Green Roof and building code review would be required to determine
any restrictions/requirements for access for maintenance purposes. Construction
could occur in 2007.
Like
the Civic Centre, energy savings and reduction of stormwater runoff will be
limited given the size and nature of the project (“extensive” vs. “intensive”
green roof) and would also vary depending upon the type of Green Roof system
specified. Furthermore Staff is advised that the air circulation requirements
of a swimming pool would further reduce the potential for energy savings. To
better compare the benefits of a Green Roof installation, Staff recommends that
the RFP specify all proposals for the Green Roof on Centennial Community Centre
include an analysis of the projected return on investment.
Appendix
2 to this report provides a comprehensive comparison of the 2 current possible
retrofit locations – Civic Centre and Centennial Community Centre, based upon
criteria developed by the City of
3. Green
Roof Installations on Future Municipal Buildings
A number of new municipal
facilities are being considered for approval at this time which may be suitable
for a Green Roof installation. They include replacement of the Ward building at
the
4. Green Roof/Demonstration Garden over
Parking Garage at Great Hall Entrance to Civic Centre
Another potential
location to consider a “Green Roof” as recommended in this report, is over the
parking garage at the Great Hall entrance to the Civic Centre. The interlocking
pavers in front of Civic Centre Great Hall have deteriorated and require
replacement. The rehabilitation of the area in front of the Great Hall entrance
provides an opportunity to beautify the front entrance of the building by
developing a demonstration garden (such as a low water garden), a portion of
which would technically be an “intensive” Green Roof since the underground
garage lies below the front entranceway of the building. This could be
developed in the context of the Civic Centre Master Plan and constructed in
phases over time. (The preferred master plan concept and
accompanying report is anticipated to go to Council in the 4th quarter
of 2006).
This improvement would
reduce the overall hard surface at the front of the Civic Centre and increase
the existing landscape areas, which would have positive environmental benefits.
The “intensive” Green Roof/demonstration gardens would beautify the main
building entrance and an information display about the Green Roof on the Civic
Centre could be featured there.
A plan for rehabilitation
of the interlocking paving along the entire front of the Civic Centre could be
developed, consistent with the Master Plan and that the portion of the Green
Roof/demonstration garden located at the Great Hall entrance could potentially
be completed as an early phase of the interlocking paving stone replacement
plan. The area identified for the Green
Roof/demonstration garden could also be used for an information display about
the Green Roofs. A budget of $150,000 has been approved in the 2006 Capital
Budget for removal and replacement of the interlocking pavers which could
instead be used towards these improvements.
Urban Design Staff recommend that
the consultant who has been hired to prepare a Master Plan for the Civic Centre
(Paul Nodwell) be retained to provide
detailed landscape design drawings and contract administration for replacement
of interlocking paving stones and the expansion of the existing landscape areas
across the entire front of the Civic Centre building; and, an “intensive” Green
Roof”/demonstration garden at the Civic Centre Great Hall entrance; at a cost
not to exceed $20,000. This would be funded from the 2006 Capital Project for
Civic Centre Improvements ( # 7014) and installed in phases over time.
Green Roof
Symposium
Town staff met with
FINANCIAL CONSIDERATIONS:
This report proposes the following expenditures:
1. Up to $10,000 to retain a consultant to prepare a Request for
Proposal (RFP) and provide technical assistance for construction of an
“extensive” demonstration Green Roof on the 2nd floor (southwest
wing) of the Civic Centre as described in this report, to be funded from the
Asset Management Project Greenroof Phase 1 Civic Centre Account (#56-5350-6789-005);
2. Up to $20,000 to retain the consultant
preparing the Master Plan for the Civic Centre (Paul Nodwell) to provide
detailed landscape design drawings and contract administration for:
·
replacement
of interlocking paving stones and the expansion of the existing landscape areas
across the entire front of the Civic Centre building; and,
·
an
“intensive” Green Roof”/demonstration garden at the Civic Centre Great Hall
entrance;
at a cost not to exceed $20,000 (funded from the 2006
Capital Project for Civic Centre Improvements # 7014);
3. Up
to $5,000 as seed money for a Green Roof Symposium in the Town of Markham with the non-profit association, Green Roofs for Healthy Cities, to advance knowledge about Green
Roofs, establish working relationships, explore grants opportunities for Green
Roof projects to be funded from the Markham
Sustainability Fund (Account #87 2800168).
BUSINESS UNITS CONSULTED AND AFFECTED:
The following Business Units are directly affected:
CONCLUSION
Developing a Green Roof
demonstration project in the Town of
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Stuart Taylor Director of Strategic Services |
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Jim Sales Commissioner
of Fire and Community Services |
APPENDICES:
Appendix 1 Overview of Benefits of Green Roofs
Appendix 2 Comparison of Civic Centre and
Centennial CC for Green Roof Project
Appendix 3 Civic
Centre Roof Plan
Appendix 4 Background
information on the Green Roof Symposia
Appendix 5 Centennial
Roof Plan
APPENDIX 1
Overview of
Benefits of Green Roofs
This section provides an overview of benefits
generally attributed to Green Roofs based upon current research studies
prepared by the City of
Much of the water volume
accumulated on a roof is discharged into the drainage system from traditional
rooftop storage systems. Green roofs can delay and reduce the peak runoff rate
and volume, depending upon the time of year, volume and intensity, or rainfall
and a number of other variants. Numerous studies have demonstrated that a
properly installed and maintained green roof will absorb water and release it
slowly over time, as opposed to a conventional roof where the storm water is
immediately discharged. This is a major benefit over conventional systems.
Also, in contrast to traditional rooftop systems, Green Roofs can offer quality
control potential by direct uptake of pollutants by plants or, by binding
pollutants within the growing medium.
There is
scientific evidence that Green Roofs offer improved energy efficiency in roof
systems. Green roofs can moderate heat flow through a roof by providing
shading, insulation and evaporation, which reduces the energy demand for
heating and cooling and hence, greenhouse gas emissions. Energy savings from
Green Roof technology depends on a number of variables such as climate, type of
heating/cooling system, architectural design, and energy sources.
In summer, the air temperature
in urban areas can be several degrees higher than in undeveloped areas. This is
known as known as the “Urban Heat Island Effect”. The increased temperature in
urban areas is largely due to the increased amounts of paving or roofing (dark
surfaces absorb more heat from the sun) and reduced vegetative cover that
normally reduces the heat. The increase in air temperature results in an
increase of energy consumption due to increased use of cooling equipment, in
turn, increasing demand on hydropower which increases pollution caused by power
generating stations through the burning of fuels. Limited information exists on the impacts of Green Roofs on the
Urban Heat Island but there is a general indication that increased vegetation
decreases air temperature. If widely adopted, Green Roofs could reduce the
urban heat island effect.
Green roofs can provide
shelter, food (from seed bearing plants) and shade to a multitude of airborne
species, such as birds and butterflies. Some Green Roof installations have been
specifically designed to provide habitat for butterflies in an attempt to
re-balance the urban natural habitat loss. In
Rooftop gardens on building
roofs can have aesthetic and recreational benefits. The type of Green Roof
required for this use, however, is generally of the “Intensive” variety. This
requires that sufficient roof load capacity be available to support the medium
required to grow larger plant species and for public access. Few opportunities
exist to accommodate “Intensive” Green Roofs within the existing buildings.
Possible future buildings may be designed to provide the required loading for
rooftop gardens including private developments, Senior Centres and
institutional buildings (hospitals, schools and community centres).
As conventional roofing
materials are exposed to solar radiation over time, the elasticity of the
materials are reduced and eventually fail to respond to temperature changes
resulting in cracking. Green Roofs offer protection to conventional roofing
surfaces from solar radiation (ultra violet rays) and other weather conditions
and act to significantly reduce surface degradation, as well as reducing the
expansion/contraction cycle. Existing data suggests that Green Roof systems can
extend the life expectancy of a conventional roof by a factor of 2 to 3 times.
The reduced rate of roof membrane replacement results in cost savings. Some
additional cost savings may result from the reduced volume of roof landfill
waste. Other benefits of green roofs that are cited include the potential for
noise reduction, horticultural therapy gardens and potentially an increase in
the fire rating for the roof.
APPENDIX 2
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Comparison of Civic Centre and Centennial CC for
Green Roof Project |
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Criteria |
Civic
Centre (2nd and 3rd
Levels) |
Centennial
CC |
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Function
as a Demonstration Site |
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Central - within |
McCowan and |
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Does not improve building aesthetics |
Green roof would improve
building aesthetics for neighbouring area as the roof is slanted and visible |
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2nd floor - potential
public access pending Building Code review 3rd storey - no
public access |
No public access |
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Green roof on 2nd
and 3rd floors would be visible from neighbouring high rise tower
and future Markham Centre 2nd floor green
roof would also be visible from inside
building |
Roof is slanted and visible
from neighbouring intersection |
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Yes |
No access therefore no view
to surrounding landscape |
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2nd floor – 1020
m2 3rd floor – 1335 m2 |
1000 m2 |
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2nd
floor - estimated $150,000 -$225,000 3rd
floor - estimated $190,000 - $290,000 |
estimated $126,000 |
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Structural |
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Minimal |
Minimal |
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May require ballast
replacement |
Yes |
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Cost |
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2nd Floor - Minimal costs anticipated 3rd Floor - Not
accessible |
Not accessible |
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Very Good - Can easily
monitor plant growth, maintenance and installation reliability |
Good |
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0 Years extension of Roof
Life Cycle |
20 Years extension of Roof
Life Cycle |
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Performance |
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Dependent upon roof system
specified |
Dependent upon roof system
specified |
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Improved aesthetics, environmental
enhancements, reduction in stormwater runoff will dependent upon roof system
specified |
Same, except green roof
replaces green space lost due to expansion and Energy savings limited due to
air circulation requirements for swimming pools. |
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Return
on Investment |
2nd
floor – minimal due to inverted roof design 3rd
floor – as above |
Estimated value
to extend roof life is $80,000 (skip one roof replacement) |
|
Timing |
Construction potentially
summer 2006 |
Construction potentially
2007 |
