What's the Difference?

“New construction” roof drains vs. “Retrofit” roof drains. Both serve the same vital purpose – remove water from the roof surface before it can damage the roofing system and, potentially, the building itself and its contents. So, what is the difference? When should each be used?

The key distinction between the drain types is how they are connected to the building’s plumbing system. New construction drains connect to the outside of the pipe, providing maximum water flow capacity. Retrofit drains connect to the inside of the pipe; the old strainer and clamping ring are removed and the new drain is slid into the pipe. Simple, yes, and effective. But it reduces the pipe’s diameter and, thus, its capacity. Water will still leave the roof, but more slowly. The potential for clogs increases. If the roof already has drainage issues, they could become worse.

Installing a new construction roof drain is, therefore, always preferable. But sometimes it is not feasible. That is where retrofit drains come in.

For example, if a bolt attaching a drain to the roof has snapped off or a tab on the clamping ring has broken, a retrofit roof drain can fix the problem without the need to open up the ceiling below to connect it to the plumbing system. It will bypass the damaged parts of the original drain and send water to the existing drain bowl. No drywall repairs required.

A new construction roof drain should always be the first choice. But when that is not a viable option, a retrofit roof drain is a simpler and less intrusive … and still effective … solution.

Mule-Hide Products offers new construction and retrofit roof drains to meet the needs of any project. Learn more here.

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