Ponding Water On Single Ply Roof

Men single ply and liquid applied roof membrane assemblies be designed to provide positive drainage.

Ponding water on single ply roof.

Pools should drain away without causing any damage to the structure but owners and managers should know when to take action how to identify the cause of the ponding and how to resolve it. The material used to seal flashings on a roof are mostly tar based products. Membrane roof sys tems 2011 states. Ponding is the unwanted pooling of water typically on a flat roof or roadway.

The nrca roofing manual. Challenge the adhesives used to make field fabricated single ply laps thus compromising the integrity of the roof system. Water on the roof will collect all the loose debris and litter and this will then become clogged in your drains and pipes making the ponding problem even worse. Ponding water can exacerbate problems for all roofing systems.

Ponding is the phenomenon of water pooling on flat roofs after storms snow melts or heavy rains. Seal seams with either a three course repair using karnak 502 karna flex and karnak 5540 resat mat or use karnak 550 patch n go fleece tape covered by a layer of 502 karna flex. Ponding or standing water can occur from insufficient drainage or a number of other reasons. Bur built up hot asphalt roofing excludes ponding breaks down and can support vegetation including moss and fungus.

Ponding water accelerates the deterioration of many materials including seam adhesives in single ply roof systems steel equipment supports and particularly roofing asphalt. On low slope asphalt roofs ponding water allows the oil solvent components of the asphalt to leach out and evaporate leaving the roof membrane brittle and susceptible to cracking and leaking in the ponding location. The membranes themselves will hold water. Most of the equipment is located on the roof during reroofing with the exception of the dumpster or dump truck required to accommodate the removal of the existing roof which will be required for both roofing systems.

For single ply roofs such as epdm tpo pvc and hypalon. You ve got to have good seams with single ply because if you don t you don t have much. Reinforce and seal membrane seams in the ponded areas and extend 6 feet beyond. The criterion for judging proper slope for drainage is that there be no ponding water on the roof 48 hours after a rain during conditions conducive to drying.

Perhaps the most common reason is water damage to the substrate or insulated board stock. Persistent leaks can cause these materials to eventually break down or settle creating a place where water can accumulate into stagnate pools. Ponding water is typically a sign of a drainage problem that needs to be addressed because when left unaddressed ponding water on a roof can. Leaks can result when single ply membrane roofs are installed with poor seams.

Tpo membranes do not exclude ponding water from the warranty and is not affected by such conditions. This means that over time and with the added water the seals will deteriorate.