Pooled water is one of the worst things for your roof. Ponding is especially common on flat roofing of commercial buildings. Poor drainage is the most common reason for ponding and this occurs as a result of incorrect installation of the roofing. Roof contractors need to account for the need to drain water when installing a roof. Water can pool in different areas and cause all kinds of problems. Even if your roof is installed correctly, exposure to extreme weather can damage your roof over time. This affects the drainage and will allow water to collect. When investing in drainage, you want to remember that you want 90% of the water off your roof within 48 hours of a rain event.
What is the Best Material to Use for Roof Drainage Systems?
How Ponding Water Damages Flat Roofing?
Ponding water is damaging as water is heavy and when allowed to sit can weigh the materials down causing damage to the materials beneath it. Ponding water can damage a flat roof in several ways.
- Dirt and other debris can accumulate on your roof – Derbs can get caught in the water and begin to rot which will then cause algae and other bacteria to grow. This damages the roof coating and materials leaving them weakened and vulnerable.
- Ponding water damages the protective coating – Constant contact with standing water decreases the stability of the coating. When the sun heats this pooled water up during the day, it can destroy the roof coating. Your roof is left vulnerable to the elements.
- Ponding water damages your roof’s membrane systems – Ponding water will seep through membrane seams and as the sun heats the water, the membrane is weakened, and leaking into the building occurs. Damage caused by leaks allows water into the roof and during colder weather, this water can freeze. This leads to major damage to the interior of the roof, dramatically reducing its lifespan.
What You Can Do to Protect Your Roof
As every roofing system is unique, these are the recommended steps you can take to protect your roof from pooling water.
- Install a better drainage system – You can correct a poor drainage system by adding a roof drain. You will need to open the existing roof down to the deck and core a hole through the deck. You can then set the new drain assembly. A pipe will connect the existing drain to the new drain assembly and you then tie the new drain assembly to the roof’s existing drain system.
- Install a tapered roof – this will keep water from ponding on top of your flat roof by directing water to the building’s internal drainage system. Tapered roofs are installed at an angle that naturally leads water toward gutters or internal drains. You can also replace the roofing membrane if either of these options is too expensive. There are many PVC membranes options that are specifically designed to prevent pooling water. In addition to this, it also helps to develop a proper maintenance schedule. Checking your roof regularly will go a long way in protecting the roof and reducing the chances of pooled water damage.
Check the roof regularly for ponding!
- Add additional drains to the roof system if ponding is excessive.
- Have the drains professionally cleaned.
- Keep downspouts and drain pipes clear from blockage.t
- Schedule regular inspections with a professional contractor.
Choosing a Membrane System
PVC and cast iron are the top options for commercial construction. They are affordable and easy to use. There are a few things you need to consider when making a decision about which material to use for your roofing membrane.
- Durability: Cast iron often lasts significantly longer than PVC piping but it is more susceptible to rusting. The lifespan of PVC is harder to predict, only because it has not been used in roofing as long as cast iron. PVC has a lower temperature limit and a higher expansion rate, but PVC is not fireproof.
- Cost: The cost for installation of PVC piping is significantly lower than that of cast iron and PVC is easier to work with. PVC does require more hangers and supports compared to cast iron.
- Noise: PVC piping noise is much greater as compared to cast iron because it is less dense. It also does not have the dampening effect that cast iron provides.
You will have questions regarding roofing membranes, materials, and proper drainage and we are here to help. Contact us today to get your roof ready for any weather. We will help you make sure ponding water is never an issue and that your roof will remain in top shape for longer.