How To Stop Water Pooling on Flat Roof

How To Stop Water Pooling on a Rooftop

You came here because you want to know how to stop water pooling on your flat roof.

Having a flat roof can have a lot of benefits to it. But there is one definitive downside to those flat roofs: pooling water. This is because flat roofs do not drain water as effectively as their pitched counterparts. Those pitched roofs have a natural slope where the water can run down, draining off the roof.

Because these roofs don’t drain water that well, they are prone to developing what is known as ponding water. Ponding water is known in the roofing community as water that stands in a puddle on the roof for more than 48 hours at a time.

Ponding water might not be an immediate threat, but if it is allowed to persist over time, that water can begin to wear on the roofing membrane. This leads to a decline in the membrane’s lifespan and can lead to things like leaks which can cause serious problems for the rest of the building.

Thankfully, there are a few different tactics that you can employ to resolve those ponding water issues on your flat roof. And it is important that you address this issue because of the aforementioned leak potential.

Flush Existing Drains

Like the drains that live in your home, drains on commercial roofs can eventually become clogged with debris. In more extreme cases, these serious clogs can actually lead to standing water becoming a mainstay on your roof.

To prevent that buildup of debris, try removing sticks, leaves, and any other rooftop debris from the drainage system of your building. Not only will this allow rain and melting snow to flow away from your building, but it will also prolong the life of your drainage system as well.

On its own, that debris seems harmless. But when it builds and builds, it can lead to a variety of issues with not only your roof but the drainage system as well. Take those preventative measures and you should not only see a longer life for your drainage system but your roof as well.

You can also hire a professional roofing service to come out and perform those preventative cleanings on your drainage systems once or twice per year. That should be adequate to keep your drainage system clean and working optimally.

That bit of preventative maintenance might cost a little money in the short-term but will save you a lot of time, money, and trouble in the long-term.

Fix Low Spots

Despite the fact that they are called flat roofs, commercial flat roofs aren’t always completely flat. This is because there are subtle slopes in the surface of the roof that can come as a result of the installation process, weak spots in the roof, or a particular focus of debris or precipitation.

Additionally, qualified contractors understand how to slope a flat roof for drainage. These slopes are meant to facilitate drainage so that there is not a lot of pooling water on your roof. It helps to remove that extra water off to the edges of the building, where an external drainage system lives, or to designated internal drains that will carry the water away.

One of the flaws of these low spots is that water ponding can occur quite easily. When that happens, the drains can clog with debris and fail to do their job. This leads to a buildup of water that can cause damage to the membrane of the roof and eventually cause leakage.

A professional roofing contractor will be able to fill in those lose areas with a roof plaster in order to better direct that water towards the drains. Again, the goal is to direct as much water as possible to the internal or external drains that your building possesses.

How To Slope a Flat Roof For Drainage

Add more drain lines to the building

If the current drainage system has issues with effectively removing water from your flat roof, there are a few things that you can look into in order to help the process along. Though it comes with additional costs, adding additional drains is one of the most effective ways to take care of this issue.

Flat roofs, particularly those in areas with high precipitation, will sometimes need those additional drains to properly clear the water from the roof. Unfortunately, most building owners don’t realize this until they see that water ponding becomes a substantial problem in the wake of a heavy storm.

Most professional roofing contractors worth their salt can install extra drain lines or even widen the existing drains attached to your building in order to direct that excess water away from the rooftop.

Again, this is an extra cost and most building owners will stray away from this option. Still, if there is a more efficient option than this, it isn’t out there.

Install Roof Crickets

When it comes to pooling on your flat roof, you might find that the water ponds in specific areas. These areas typically are near chimneys or around large vents. The best way to battle water ponding in these areas is to install roof crickets in those areas.

Crickets are ridged structures that have been designed to divert melted snow and rainwater around roofing obstructions like the aforementioned chimneys and vents. Because of their positioning or design, those obstructions may have a naturally difficult time draining water on their own.

Adding crickets to these obstructed areas can also help when standing water is typically associated with transitions between the areas of the roof. If you are experiencing ponding water in other areas of the roof, crickets might not be enough. It is important to know how to drain water from a flat roof.

But if most of the standing water revolves around those aforementioned obstruction areas, installing roof crickets can be the remedy that you have been searching for and answer your question as to how to divert water on a flat roof.

How To Drain Water From a Flat Roof

Re-pitch The Rooftop

One issue that your commercial building roof could be having when it comes to keeping away ponding water is that the pitch was not properly designed or installed during the initial process. All roofs need some form of sloping to it, even if it is just subtle.

Without the right amount of sloping, the water that builds during a storm won’t be able to drain and will more often than not lead to additional pooling across your flat commercial roof.

The process of re-pitching the roof might be a costly one, but it might also be the only way that you can solve consistent ponding issues on your commercial roof. It might be worth exploring other options first, but if you need to make the investment, there are far worse things to put your money towards.

Best of all, if you know what you are looking for, you can actually re-pitch the roof before a problem arises. Sure, noticing standing water is an obvious sign, but maybe you live in an area that has a lot of storms and want to take preventative measures.

Replace The Membrane

The membrane of your roof is the protective layer that keeps your roof safe from things like moisture getting into the roof, attic, or other areas of the building. When that moisture builds up in the structure of your building, it can cause substantial structural damage.

When the membrane becomes damaged – and this can happen for a variety of reasons, ponding water chief among them – it might be worth simply getting a new membrane for the roof. This is an option if the cost of replacing the roof is not an option.

There are many membranes out there that are meant to withstand ponding water so it might actually be a blessing in disguise if you have to replace the membrane of your current roof for a more effective, modern version. An inspector will know how much ponding is acceptable on a flat roof.

You can also perform preventative maintenance to ensure that the membrane stands the test of time. Bring in a roofing contractor to perform an inspection once or twice a year to ensure that the membrane is holding up and not worn or damaged in areas.

Damaged Flat Roof Membrane

Compress Insulation

Another problem that can be combated with frequent inspections, compressed insulation can be another leading cause of ponding water on your commercial roof. You can also have serious issues with your roof if that insulation is insufficient.

Compressed insulation is generally caused by heavy roofing equipment that rests on the insulation during the installation process. Also, repeated treading over the roof area can lead to indentations in your roof that can lead to pooling as well.

The message here is that you need to ensure that the proper precautions are taken with the insulation and during any inspection processes. It is all too easy to damage the roof through these processes when some care could save you a lot of time and money.

Keeping your commercial business roof working optimally is one of the most important aspects of owning that building. That roof is the last line of defense you have from the elements and it needs to work properly.

With preventative maintenance and a little attentiveness, you can keep your roof working the way it is meant to work. Don’t let ponding water become an issue for your business when you can use these tips to get rid of that pesky water.