Case studies - Living Roofs in Integrated Urban Water Systems - page 153

planters also drains into the drain ield and connects to the at-grade SCMs (Hart
2014).
Like the Port of Portland Headquarters project, the overall performance of the
Mirabella's living roofs are yet to be assessed because of how recently the build-
ing was constructed. A water meter was installed on one of the irrigation lines
during roof installation, but roof monitoring equipment is not widespread
throughout the building to provide a comprehensive analysis of water consumed
for irrigation (Hart 2014). A 3-5 year plan is in place to monitor the performance
of the Mirabella. Data collected will be compared with that of neighboring build-
ings in the South Waterfront District. Full occupancy of building was reached only
in January 2013, so it is dificult to assess exact resource use beneits (including
energy and water consumption), as the numbers are constantly changing (Patter-
son 2014).
3 LESSoNS LEARNED
The Mirabella project suffered from an incipient planning process that did not
stress the importance of a maintenance legacy and did not effectively deine con-
sultant responsibilities post-construction.
The lack of a maintenance manual has resulted in living roof maintenance
problems. The living roof is given a visual check from time to time during the fall
and winter months to ensure plant health, and irrigation is monitored by the
assembly installer once a week during the summer months. However, it was dis-
covered that the roof membrane of the twenty-ifth loor living roof had been
compromised by a roof protrusion, causing damage to the residence below. Due
to the unclear chain of liability, which should have been clearly outlined in the
design contract, no member of the consultant team was willing to take responsi-
bility for the compromised roof membrane (Patterson 2014). To date, the leak
has been repaired once, unsuccessfully, but the area remains unplanted (Hart
2014). The current building facilities manager has expressed frustration and
regret at the lack of available general information on extensive living roofs, how
they function, are assembled and maintained. In particular for this site, there is a
lack of information on leak repairs including who to contact and what proce-
dures to follow. Despite the many successes of the project, Mirabella is a caution-
ary tale for current and prospective building owners and their maintenance
teams.
Another lesson learned is that due to the fear of life-safety liability held by
building owners, accessibility to living roofs is sometimes hampered. This means
that the design intentions for rooftop accessibility in the planning phase must
be communicated to the building owner/future building management and cal-
culated in the risk management of the building's operations. Despite the design
team's well-intentioned goal of allowing residents to pursue urban agriculture
and gardening and providing the necessary life-safety elements (the design team
speciied easy-to-maintain plants for the twenty-ifth loor garden, and designed
adequate guardrail provision), the Mirabella operations administration does not