Flat roofs face a different set of challenges than sloped roofs. And while there are significant advantages to flat roofs on commercial buildings—lower cost, easier access, more efficient use of space—they are no less vulnerable to leaks.
If you suspect a leak in your commercial flat roof, your first step should always be to contact a commercial roofing professional who can inspect your roof and determine the source of the problem. It also helps if you understand the reasons why flat roofs leak and how you can prevent it.
Ponding Water
Standing or “ponding” water is one of the most common causes of leaks on flat roofs. Flat roofs are naturally more susceptible to standing water than roofs built on an incline. Any water which stays on the roof for longer than 48 hours following a rainstorm is considered a potential problem. The longer it stays there, the greater the likelihood it will eventually cause damage.
Of course, flat roofs aren’t exactly flat. Most have a slight, imperceptible pitch to help water drain more effectively. Even so, roofs can develop low spots over time. The roofing material can weaken in a particular area simply due to wear-and-tear from the elements. These areas become more prone to standing water. Keeping up with maintenance will allow you to catch these problem areas before they become leaks.
Flat commercial roofs are also designed with drainage systems to make them better able to shed water. This is helpful, but even well-designed roofs can suffer from clogs in the drainage system. The drains themselves can become blocked by leaves, dirt and debris, as can the gutters and downspouts. Routine roof maintenance is crucial to keeping drains clear so water can easily be directed off your roof.
Damaged Membrane
Older commercial roofs were made with BUR, or built-up roofing. Built-up roofing gets its name from its installation method, which requires it to be “built up” in layers. These days, most modern flat roofs are covered with a thin, single-ply layer, often referred to as a membrane. It’s most commonly made out of some sort of durable, waterproof rubber (though there are many flat roof membrane materials to choose from). Roofing membranes are not only durable and effective, but also more economical and easier to install than older roofing materials.
Still, roofing membranes are still vulnerable to time and the elements. As years go by, they may eventually blister, crack, get punctured, or tear. This allows water to penetrate the membrane, causing a roof leak. Fortunately, one of the great advantages of roofing membranes is they are relatively easy and inexpensive to repair or replace. But you must have your roof inspected on a regular basis—ideally at least once a year—to make sure the membrane is in good shape.
Environmental Causes
The elements have a way of really punishing flat roofs, especially here in the Twin Cities area. They are exposed to the weather’s wild mood swings year-round. High winds can tear roofing loose and send tree branches crashing down. Heavy rainstorms can drop more water than even a well-designed drainage system can quickly whisk away. Hail can cause damage to parts of your roof not visible to the naked eye.
Hot summer summer sun causes roofs to expand and contract due to heat and heavy winter snowfall may prove to be more than some roofs can take. No matter what the calendar says, it’s always important to inspect your roof after a severe weather event. If you suspect damage of any kind, always contact a roofing professional as soon as possible. We’ve seen too many roof replacements which could have been avoided if action had only been taken sooner.
Learn More
If you’re experiencing trouble with flat roof ponding or other issues which may cause leaks, it’s always important to work with a roofing professional who specifically understands the challenges faced by flat commercial roofs. General contractors don’t always have the skills and experience to work on commercial roofs and you could void your warranty by having your own facilities team attempt repairs.
Find a commercial roofing company you trust and continue working with them again and again. This allows your roofing professional to establish a relationship with your roof. They can then develop a maintenance program to target your building’s unique needs. This is the only way to cut off potential roof issues before they develop into serious problems.
Contact Midwest Roofing, Siding & Windows, Inc. today to learn more about how we can help keep your flat roof safe and secure. Our team has been providing exceptional commercial roof maintenance and repair in the Twin Cities area for more than 40 years.