Ponding is the retention of water in low-lying areas of a roof deck or plaza long after precipitation stops. The industry standard defines it as water remaining for 48 hours under conditions that normally promote drying. Chronic ponding accelerates the degradation of roofing membranes, voids manufacturer warranties, and adds massive dead load to the structure.
We have severe ponding around the scupper on the north elevation, and the resulting mud has clogged the drain completely.
A one-inch deep pond covering a 20-foot square area adds nearly a ton of dead weight to a roof deck.
Also heard as
- standing water
Related terms
Positive drainage
A design and construction condition ensuring that all water flows away from surfaces and drains completely within 48 hours.
Hydrostatic pressure
Pressure from standing groundwater against a wall or slab, rising with the depth of water above that point.
Leaker
Any window, joint or unit that is letting water in, as tracked on a leak investigation punch list.