Problem:
No overflow 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.
Solution:
Install a secondary scupper
2 inches higher than the primary scupper to drain excess water in case the primary scupper becomes blocked.
Problem:
Clogged roof drain.
Failure to clear away leaves from a drain strainer can cause ponding.
Solution:
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 drain.