Roof Ponding

Ponding on Low Slope Roofing

Roof Ponding is the retention of water on a low-slope or flat roof caused by a deflection of the roof's underlying structural components. Ponding water on a roof causes leaks, algae and fungi growth. If left unattended, roof ponds can lead to the collapse of a roof.

The size of roof ponds increases over time because the weight of the water causes additional deflection of the structural membranes underneath. Eventually, the structure will not be able to carry the increased load and the roof collapses.

Repairing Roof Ponding

Whenever feasible, ponding water should be rectified before any roof coating application can proceed. Sometimes, the easiest way to fix one large pond on a roof is to put a roof drain at the lowest point of the pond. Another popular method is to install Sprayed Polyurethane Foam (SPF) on the roof.

Roof Ponding over Asphalt Built Up Roofs (BUR)

Roof Ponding over Modified Bitumen Roofs

Roof Ponding over Single Ply Roofs