scupper. The parapet wall around this roof has only one
scupper on each side, with no overflow scupper. If the primary
scupper becomes blocked - by a tennis ball, for example, or in
this case, a soda can - then not only are leaks likely to
occur, but ponding water on the roof could get heavy enough to
threaten the structural integrity of the roof framing.
Install a secondary scupper
2 inches higher than the primary scupper to drain excess water
in case the primary scupper becomes blocked.
Clogged roof drain. Failure
to clear away leaves from a drain strainer can cause
Remind homeowners to check roof drains
and scuppers regularly,
and to clean them at least
once a year - preferably more often. An overflow scupper is
needed here, as well - no roof should ever depend upon a single