Ponding Water On Single Ply Roof

Ponding water accelerates the deterioration of many materials including seam adhesives in single ply roof systems steel equipment supports and particularly roofing asphalt.

Ponding water on single ply roof.

Ponding is the phenomenon of water pooling on flat roofs after storms snow melts or heavy rains. 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. A small cut or puncture in a roofing membrane may cause minor damage on a well drained roof surface but the same puncture located in an area of standing water may allow significant water infiltration causing damage to the roof insulation roof deck and building contents. Tpo membranes do not exclude ponding water from the warranty and is not affected by such conditions.

Leaks can result when single ply membrane roofs are installed with poor seams. 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. 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 water is typically a sign of a drainage problem that needs to be addressed because when left unaddressed ponding water on a roof can. This means that over time and with the added water the seals will deteriorate. The membranes themselves will hold water. Membrane roof sys tems 2011 states.

The nrca roofing manual. Allow areas to completely dry then apply karnak 229ar elastomeric brush grade over the ponding area and extend 6 feet beyond. 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. Challenge the adhesives used to make field fabricated single ply laps thus compromising the integrity of the roof system.

Ponding water can exacerbate problems for all roofing systems. Ponding or standing water can occur from insufficient drainage or a number of other reasons. Reinforce and seal membrane seams in the ponded areas and extend 6 feet beyond. The material used to seal flashings on a roof are mostly tar based products.

Persistent leaks can cause these materials to eventually break down or settle creating a place where water can accumulate into stagnate pools. 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 is the unwanted pooling of water typically on a flat roof or roadway. You ve got to have the seams either glued or heat welded properly harriman explains.

Perhaps the most common reason is water damage to the substrate or insulated board stock. Men single ply and liquid applied roof membrane assemblies be designed to provide positive drainage.