Proper and efficient drainage on your commercial roof is essential in ensuring continuous and unimpeded water flow during peak times. In the event of a storm, you want to know that your roof drains the water properly, which will avoid potential damage to the entire structure. It’s important to choose the right type of roof drain system to ensure efficient drainage no matter what kind of business you run:
- Retrofit roof drains
- Full size replacement roof drains
- Copper drain bodies
- Aluminum drain bodies
- Clamping rings
- Control flow weirs
Your roofer in Toronto will work with you to weigh the pros and cons of each and determine the best type of drain for your roof. Today we will discuss retrofit vs. full size replacement drains, copper vs. aluminum drain bodies, the advantages of utilizing clamping rings, and control flow weirs to regulate drainage in commercial roofs.
Retrofit commercial roof drain vs. full replacement: cost and effectiveness
There are two types of roofing projects: new roofs and replacement roofs. With replacement roofs, you have the option of putting in a retrofit drain inside the existing drain and rain water leader or replacing the existing drain by removing it and connecting a new one to the existing rain water leader.
Option 1: Replace the drain
To replace the drain, you need to hire a plumber who can cut the drain connection inside or remove the clamp, take the old roof drain out, and put a new full sized one inside the rain water leader and make the new drain connection.
- Advantage: With this option, you’re essentially replacing like with like. For example, if you have a three-inch existing drain and install a new one that’s the exact same size, the fit will be precise with no constriction of water flow.
- Disadvantage: With this option, there is an extra cost for the plumber to make the connection.
Option 2: Install a retrofit drain
Installing retrofit drains for flat roofs, on the other hand, will save you the cost of the plumber but poses its own unique set of challenges. With a retrofit, the new roof drain slides inside the existing one, creating a difference in size. While it may appear like a minor discrepancy, it actually makes a big difference because it will result in a smaller flow. This is especially important during heavy rain storms.
The backflow preventer that gets installed with a retrofit drain can address this. However, there is always a risk of failure because:
- there are a range of available types of backflow preventers with some good, better and best options available in the marketplace,
- there is always the risk that the rain water leader pipe is deformed and not completely round and therefore the backflow preventer cannot sit properly and perform its intended function, or
- simple workmanship installation issues.
It’s just another element to the system that wasn’t there before, and can pose risks that wouldn’t be present with a complete replacement.
- Advantage: You will save the cost of hiring a plumber.
- Disadvantages: Flow will be restricted due to the discrepancy in size. The restriction in the flow of water, based on the reduced size of the drain opening could be as much as 25% in many cases. Also, backflow preventers can fail.
Opting for a new replacement for your roof drain rather than a retrofit offers long-term benefits for your commercial building. Efficient water roof drainage not only protects the roof from damage but also the structural integrity of the entire building.
Copper vs. aluminum: which is better for commercial drainage systems?
In terms of materials for roof drains on roof replacement projects, the two main types are copper and aluminum. Cast iron roof drains are typically specified on new construction projects but not used during roof replacements. Here at Elite Roofing, we don’t use aluminum drains as they are too soft and can get damaged easily.
Copper roof drains, on the other hand, are much stronger and can better handle large amounts of water during a storm. They cost more but over the long term, copper drains are well worth the expense. Here are some key takeaways of both materials as they relate to roof drains:
- Copper: More durable, longer lifespan, lower maintenance, resistant to corrosion, and higher cost.
- Aluminum: Lightweight, cost-effective, but not recommended by our team.
We believe it’s important to have the proper accessories in place, and cutting corners on materials is not wise.
Clamping rings: a different approach to commercial roof drainage
Most roof drains feature baskets designed to catch organic debris such as leaves or mulch as the water flows through so they don’t make their way into the drain. A clamping ring is often used to provide a stronger and more secure connection than a traditional drain design.
Essentially, it clamps the membrane and provides a mechanical connection to the drain. We prefer the use of clamping rings for the security and strength they offer over other types.
Control flow weirs: regulating water flow
Control flow weirs, typically found on new buildings, are designed to restrict the flow of water so that municipal systems don’t overflow during big storms. Thus, control flow weirs are required on new construction roofs to better regulate water flow. However, they can sometimes get clogged with debris and plug the flow of water. The water level will then rise on the roof, resulting in ponding and the potential for leaks.
Due to these concerns, it’s important to inspect your roof once or twice a year to ensure the control flow weirs are operating as they should.
Check out this quick YouTube video demonstrating the functionality and benefits of control flow weirs in roof drainage systems.
Elite Roofing can help you decide on what type of commercial roof drain is best for you
In the end, your roofer can help you determine the type of roof drain that’s right for you and/or your design team. The final recommendation will be based on the project’s needs, costs, and long-term effectiveness. This is why it’s so important to partner with a trusted roofer in Toronto to weigh the pros and cons of each element of your commercial drains. That’s the Elite Advantage.
Contact us today to schedule a quote and consultation on roof drain inspection or installation.
