May 2017
FireNuggets, Inc
Weep holes situated at a designed height in each metal tray allows water to
flow from one section to another enroute to sloping roof and drainage.
aesthetics and provide the supplementary water
retention benefits of green roofs. space void. This design allows the blue roof to
retain large volumes of rainwater.
The architect and/or engineer on a blue roof
project should follow good design practices and
the requirements of the Building Code. This will
ensure optimal performance of the blue roof
rainwater detention system. Water depth on the
roof should not exceed two-to-four inches.
Commonly, depths much shallower than three
inches are required to meet detention
requirements. Additionally, the water should not
be stored for longer than 24 hours. Excessive
rainfall may, however, still overwhelm a
blue roof, hence the design should also
include scuppers in the parapet and
overflow drains to alleviate too much
water being retained. Collapse Concern
The beauty of the blue roof can also be an ugly
reality to the firefighter. The combination of the
weight of fixed system components (dead load)
in conjunction with detained water (live load)
during and immediately following a rainstorm
can have disastrous consequences. Roofs are
built to
Note: A cubic foot of water weighs
62.4 pounds or 5.2 pounds per square
foot per inch of depth. Therefore, a
10,000 square foot roof holding 1-inch
depth of water weighs more than
50,000 pound
Another blue roof design involves the
creation of a void space beneath
concrete pavers that are installed on
pedestals. The pavers are elevated in order to
store large amounts
of rainwater.
Blue roof constructed with pedestals to support pavers and create a void
Insulated material is
space for water retention. Click here for more…
laid below the water
By Firefighters, For Firefighters
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