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| A
certified green roof professional ensures all green roof components are
installed properly. Some manufacturers also offer training programs for
installation contractors about the proper use of materials. Photo courtesy of
American Hydrotech. |
|
Installation
Period
During the installation of all green roof components, the following items
should be considered top priorities for installation teams and followed up on
by facility managers and building owners:
• Ensure all components are being installed as specified.
• Ensure that engineered growing media is at an equal and consistent depth.
• Inspect the placement of all plant material to maximize optimal
growth.
• Test and re-test all irrigation systems for proper function. (Note: If no
irrigation system is currently in place, all plant material should be “watered
in.” It is also recommended that a water source be made available on every
green roof, regardless of whether a full-time dedicated irrigation system is in
place. Simply put, plants need water to thrive, especially in the first few
months.)
Establishment Period
After installation is complete, a maintenance contract should be instituted
between the facility manager or building owner and the maintenance contractor
or, more ideally, the installation contractor. In addition to this documentation,
the following items will also need to be accomplished and repeated during the
first 90 days:
• Conduct full a walk-through, with all parties present, before the project is
deemed complete. Determine proper installation, and ensure that the contractor
addresses any installation issues immediately with installing contractors
before departing from jobsite.
• Remove and properly dispose of any excess materials or debris from the roof
surface.
• Inspect all surface drains and scuppers to ensure each component is also
clear of any debris. (Note: This element should become habit and second nature
to anyone visiting the roof at any time.)
• Dependent on various seasonal and regional aspects, the irrigation system may
need to be winterized and/or calibrated on an annual basis. Each spring all
zones should be turned on and tested for proper function. (Note: It is common
that plant material requires a greater amount of water the first 90 days than
any other period to get the plants established. If no irrigation system is
present, hand watering may be required to ensure that plants successfully move
their roots into the growth media.)
• Designate a plant manager or plant inspector who is responsible for
continually monitoring the media levels, plant material and growth to ensure
that any problems are quickly identified and resolved.
Growth Period
The first year is vital to the survival of any green roof installation. If the
roof survives this stage, it likely has a great shot at meeting all
establishment and warranty goals.
• Inspect all media and roof components for erosion issues and proper
irrigation. Any issues should be delivered to the green roof manufacturer
immediately. (Note: While some manufacturers are willing to assist their
clients well into the “growth” stage of the green roof, others may not be so
helpful.)
• În the spring after the first year of growth, a spring clean up is
recommended to aid the growth of new plants. All plant material that still has
dead flowers or stalks must be deadheaded. All vegetation-free zones (drains,
skylights, perimeters) should also be cleared of weeds or encroachment of
desirable green roof plants. (Note: Any sedum material removed can be used as
“cuttings” in the bare areas within the green roof.)
• Any plant material that may have perished during the first winter should be
replaced at this time. (Note: Some manufacturers offer warranties that include
free plant replacement.)
• Growing media that has eroded due to wind or water should also be replaced.
It is critical that a comparable media is used for any replacements. Improper
material can result in filter clogging due to high clay content or compaction,
which is undesirable to plant roots.
• A final walk-through at the end of green roof warranty period should be
conducted. (Note: Some green roof companies offer a final walk-through before
the warranty expires.)
Long Term
These steps are not always necessary but might be crucial to a project’s
long-term success:
• As-needed monitoring and testing of the growing media. (Note: Some companies
have soil experts on staff to give long-term support long
after installation.)
• Although costly, consider fertilization applications to meet the requirements
of certain plants based on their performance. (Note: It is advisable that a
plant’s fertilization needs are outlined during the design phase of any green
roof project. No fertilizers should ever be used without the consent of a
qualified green roof professional.)
• On a rare occasion, pesticide applications might be required at this stage if
there are any issues with insects on your green roof. Utilize an integrated
pest management program (IPM), and consult a qualified professional.
• While mechanical weeding is always the most environmental and economical
approach, herbicide applications are another possibility of green roof
maintenance at this stage. Be sure to consult the local municipality or
original design team for permission of use.
