Check Out The Effects of Ponding Water on the Roof

What Is Ponding Water?

Ponding Water on the Roof

Ponding water on the roof is a form of water that stays on the roof for more than 48 hours.  Ponding water is a result of rain, melting snow, or runoff from the roof’s equipment.

Ponding water on the roof for about 12-36 hours is considered normal after rainfall or snow meltdown. However, according to National Roofing Contractors Association, any form of water found stagnant on the rooftop for more than two days is considered hazardous and it must be examined by roofing professionals.

The gravitational force makes standing water buildup on rooftops extremely problematic because eventually, the water has to go down. Effects of Ponding water can significantly damage the entire roofing system and it must be examined and fixed on time.

If not taken care of on time, ponding water can cause major damage. Some of the adverse effects of ponding water are discussed below:

Effects of Ponding Water:

Effects of Ponding Water on the Roof

Coating Issues

A flat roof’s exposure to prolonged water ponding can cause the roof’s coating to absorb extra moisture. Stagnant water can have adverse effects on the stability of the roof’s coating. The roof’s coating may begin to break down under extra moisture and also the harmful radiation from the UV rays, which heats the top of the roof, can cause it to break down.

Destroyed Membrane

When the ponding water finds its way through the seam system of the roofing membrane, serious problems arise. The ponding water boils because of the sun’s heat, some areas become susceptible to leaks. The ponding water also acts as a magnifying glass and therefore ends up causing more damage to the roofing system.

All types of roofing membranes will get damaged if they will be submerged in the ponding water. A membrane may get deteriorated as a consequence of the ponding water.

Some materials like Asphalt and polymeric degrade rapidly when they are exposed to frequent rounds of ponding water and evaporation – which is a consequence of the cycles of ringing and sunlight. During winters, ponding water has adverse effects on the roofing system.

The aggregate surfacing of the roof erodes during the cold weather. When water freezes, it constantly changes forms with the changing of temperature. The frozen ponding water moves in cold seasons and scrubs the roofing membrane causing severe damage to the rooftop.

Leaks and Collapse

Ponding water finds its way into the imperfections and some areas in the roofing system, which eventually leads to leaks in the interior parts of the building. Roof leaks are not a good sign, they can cause the roof to collapse. The weight of the ponding water makes structural damage to the roof even easier.  

Invasive Plant Roots

Ponding water is not clean water, all the debris and dirt are mixed with it. Thus a mixture of dirt, debris, and stagnant water is a healthy habitat for algae, plants, and fungi. This biological growth is extremely damaging, it can cause the entire roofing system to fail.

Weakened Features

The substrate can deteriorate because the ponding water weakens the roof’s structural support at the roof deck. Constantly being exposed to water can lead to rust in the roof’s metal parts and can cause severe damage to the solid features of the roof. Wood is also most likely to soften because of frequent exposure to ponding water.

The roofing insulation can also get extremely damaged because of the ponding water, the structural integrity gets compromised because of the wet insulation. Ponding water causes the organic fibers to rot and also results in the loss of binders which consequently results in the insulation system getting weaker. Thermal resistance is also compromised, and most importantly the insulation constantly undergoes dimensional changes.

Roofing manufacturers are most likely to nullify the warranty if the water on your roof remains there 24/7. It is advised to immediately fix the issues which are causing the water to remain on the rooftop because if not dealt with on time, the ponding water can have adverse and hazardous effects.

Poor Roof Design

One of the reasons why the water accumulates on the rooftop is poor roof design. If the plans for the roof project are not coordinated with the roof and building layout then the project is most likely to have severe issues such as ponding water.

Most of the complications are not visible by only looking at the exterior of the building, for a roofer, things can get extremely complicated if he is dealing with a flat roof. There is this common misconception that flat roofs are easy to repair.  A flat roof requires proper engineering to avoid future problems.

Initial Steps to Fix Ponding Water

Initial Steps to Fix Ponding Water on the Roof

You can start by cleaning the debris and dirt from your drains. Ponding water can be avoided by adding some extra drain lines, which is a practical fix for the problem in the areas with high precipitation.

Roof crickets can be installed to avoid the rainfall from getting trapped. Cricket helps to divert water from the fixtures.


Stagnant water on a flat roof for more than 36 hours is a serious problem. We have covered above all the problems that standing water on the rooftop can cause. Ponding water must be dealt with on time to avoid issues like structural damage or leaks.

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Nishant Desai
Nishant Desai
Nishant Desai has over 8+ years of experience in SEO and blogging. His blogging expertise can organically increase online visibility and traffic for blogs and websites. With his SEO expertise, he has already contributed to iGeeksblog, Firstsportz, and Firstcuriosity. In addition, he can create content strategies, conduct keyword research, publish optimized blogs, and resolve technical issues.

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