Ponding on commercial roofs might appear to be a minor problem, particularly following heavy rain. But if the water is not draining, it could indicate a bigger issue.
The ponding water on commercial roofs can impose additional stresses on roofing materials, drainage systems, and even the structure below. Early detection can prevent costly repairs and unforeseen interruptions.
The design of a flat roof is such that it slopes slightly to allow rainwater to flow to a drainage point (such as a drain, scuppers, or other points). They are not completely level.
If water is still pooling in some places, there may be something that is blocking drainage. There are a number of problems that can cause this.
Poor Roof Slope
There can be sections of a roof with inadequate slope. The zones collect the rainwater rather than directing it towards a drain.
As time passes, these low areas can become more prominent as roofing materials grow older or the structure itself changes.
Clogged Drains
Roof drains and strainers can be clogged by leaves, dirt, branches, trash, and other debris. When the drainage path is limited, there is nowhere for rain to go.
Damaged Drainage Systems
Commercial roof drainage problems can happen due to broken or poorly positioned drains, blocked scuppers, and damaged gutters.
Check the drainage system if water continues to puddle after storms instead of draining off the surface.
Low Areas on the Roof
There are some roofs that have naturally formed depressions where water will pool. These low spots on commercial roofs can be caused by the aging of the materials, compression of the insulation, structural movement, or previous repairs.
A small amount of temporary water after rainy weather doesn’t necessarily mean there is a serious roofing problem. But water that sits for a long time should be attended to.
So, how long can water sit on a flat roof? The answer varies based on the roofing system, weather conditions, drainage design, and manufacturer requirements.
When water stays for a long time after other areas have dried, the roof should be checked to find out why it is not draining properly.
Roofing Material Damage
Roofing materials can stay moist for long periods of time in standing water. This can lead to deterioration, roof membrane issues, or premature aging, depending on the roof system.
Small weaknesses can be harder to control with repeated exposure.
Leaks
Any water that is allowed to pool around seams, penetrations, flashing, or damaged areas can provide more opportunity for water to enter the building.
The leak can be located anywhere, even outside the ponding area. Water may move through roofing assemblies prior to being visible and/or noticed within.
Structural Stress
Water is heavy. The more ponding, the more weight that can be added to the roof structure, which may not be necessary.
This can be especially worrisome if it persists after several storms.
Mold and Interior Damage
Moisture that is allowed to penetrate the structure can cause damage to ceilings, insulation, walls, stock, equipment, and other interior components.
A recurring pattern is particularly significant. If water remains in the same area of the roof after each rain, there could be a problem with the roof’s drainage or structure.
The appropriate solution will depend on the cause of the water accumulation.
Clean Drains
When the issue is a blockage, removing debris from drains, scuppers, and other drainage elements can restore normal water flow.
Regularly check commercial roofs, especially before and after extreme weather events.
Repair Damaged Roofing
Targeted repairs to damaged membranes, seams, flashing, or penetrations may help restore the roof system if they are causing water accumulation or leaks.
The damaged area should be assessed and not just temporarily covered without addressing the source.
Correct Drainage Issues
If ponding is still occurring after the drainage design, a roofing professional may suggest modifications to the drainage system to ensure water is directed where needed.
Additional drainage, redesigned drainage paths, or other changes to the roof system may be a solution depending on the roof.
Address Low Spots
If the depression is ongoing, it may need a more thorough assessment. If the insulation or structure has been compressed, it will not be fixed by removing the water.
A professional inspection will help you decide if the area requires a local repair or a more comprehensive correction.
Preventing Future Ponding
One of the easiest ways of minimizing the chances of water accumulation is by doing regular maintenance.
Have regular roof inspections, clean drainage elements, clear debris, and deal with minor roofing issues before they become major.
Major storms can also create new ponding locations on the roof, so checking the roof to see if there are any new ponding areas early can help identify developing problems.
If water continuously builds up on a commercial flat roof, it should not be overlooked. If ponding lasts longer than it takes for the rain to drain off, then it could be a sign of structural issues, low spots, damaged roofing, or drainage issues.
Early treatment can minimize the risk of leaks, material deterioration, and expensive repairs. To ensure a commercial roof functions as it should, regular inspections and proper maintenance of the roof’s drainage system are necessary.
Do not let standing water become an even bigger roofing issue. 911 Commercial Roofing can assist in the identification of drainage problems, low areas, roofing damage, and other problems that lead to ponding water.
Give 911 Commercial Roofing a call today to schedule a roof inspection by a professional and prevent expensive water damage to your commercial property.
Contact with us through our representative or submit a business inquiry online.
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