Effect of Hurricanes on Building Drainage

Hurricane Season Preparedness

Aging buildings, especially those built prior to 1985, may not be as equipped for hurricane season as you may think. This article discusses two important areas in hurricane preparedness that warrant the attention of board members and property managers. First, the dangers that old rain drainage pipes pose to flat roof drainage. Second, the effects of hurricane force winds on a tall building’s cast iron or PVC lines.

Storms, Hurricanes, and Roof Drainage

Old Rain Leaders Pose Risk to Buildings

Over the years, corrosion and debris buildup affect the ability for rain leaders to properly drain a roof. The corrosion process can drastically compromise drainage pipes’ flow capacity.

Cast Iron Pipe Corrosion

When cast iron is exposed to air and moisture it will rust and corrode. These natural elements will continue to break down the pipe, causing the cast iron to turn to rust, until the metal is completely gone. For cast iron rain leaders, the result is a narrowing diameter and reduced flow.

How Could Poor Roof Drainage Affect My Building?

Buildings are typically constructed with the right size and number of rain leaders to prevent the roof from holding water. Unfortunately, decades of corrosion may constrict cast iron rain leaders by 50% or more of the flow capacity! As a result, the roof is unable to adequately drain, and heavy rainwater can be left standing.

Let’s talk about tropical storm systems that can dump anywhere from a couple of inches to a foot or more of rain. Flat-roofed buildings are most vulnerable to damage during these high-accumulation storms. Studies show that 12 inches of water on a 20,000-square-foot roof is equal to about 1,248,000 pounds of water weight that will need to be drained through the rain leaders during the storm.

Now, if your building’s rain leaders are functioning at 50% of their original flow capacity, you could end up with hundreds or even thousands of pounds of water weighing on your roof!

If your flat roof is not in like-new condition, you could be in more trouble. A Tamarac, Florida 20-unit, 2-story condominium building’s roof collapsed after accumulating just 3″ of rain. Why did the water pool? It was due to a lack of roof drains.

Immense roof pressure from pooling water can cause leaks, and as in the example, a partial or complete roof collapse.

If there are cracks in your roof drain, a significant amount of water may also leak behind walls.

The Time to Prepare is NOW!

Storm Season 2020 has gotten off to a record-breaking start. With three named storms by June 1st (opening day), some areas have already seen weeks of rain accumulation. In fact, AccuWeather published a report on June 9, 2020 stating that this could be the fastest-starting hurricane season ever.

If you believe your building’s drainage system is diminished, we strongly advise you to take action now! A professional assessment complete with a forensic video inspection will reveal deficiencies and help you plan a course of correction.

Pipelining Technologies, Inc. is the trusted leader in restoring residential, condominium, and commercial rain leaders and sanitary vertical stacks throughout South Florida.


High Winds, Swaying Buildings, and Damaged Pipes

High-rise buildings are especially vulnerable in hurricanes and high winds. These structures tend to sway or “give” in the wind. Although typically designed to “give” during hurricane force winds without compromising the structural integrity, the cast iron and PVC pipes running vertically in the building are not built to handle such swaying. Cast iron pipes are inherently rigid. They easily develop fractures/cracks, even without much distortion. In addition, wind-driven swaying can affect both cast iron and PVC pipes by causing joints to misalign. All these factors can lead to leaks.

Crack in Cast Iron Pipes Can Be Caused By Hurricanes

PVC and Cast Iron Pipe Misalignment Due to Building Swaying

Is Your Condo Ready for Hurricane Season?

South Florida’s aging condominium buildings coupled with exposure to hurricanes, present a heightened concern for board members and property managers.

As discussed above, a roof collapse could cause injuries or perhaps deaths. Leaks and other damages to vertical stacks could facilitate the growth of toxic mold, standing water on the roof, water leaking into walls, and damage to the building and its residents.

We highly recommend having a professional video inspection done of your building’s rain leaders and sanitary vertical stacks, to make sure you are ready for hurricane season. You can count on Pipelining Technologies, Inc. to take care of your drainage pipe needs.

Keep your residents safe throughout this storm season!

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