Floor drains are set into workroom floors, kitchen floors, bathroom floors and some types of showers. They are needed anywhere large amounts of water often spill, or in any floor that is regularly washed down. Two of the most common types of floor drains are hub drains and no-hub drains. If you are installing your own floor drain system, you need to know the differences between the two, so you can install the right type of drain for your job.
Hub Floor Drains
A hub floor drain is a drain set into the floor that is connected to the drain pipe by means of a hub coupling. The end of the drain flares out like a funnel. This wide section is meant to slip over the end of the drain pipe beneath it. Metal hub drains and pipes often require soldering to seal them together, though not always. PVC drains and pipes use PVC cement or some similar chemical means of making the seal.
No-Hub Floor Drains
A no-hub drain has a lower end that is the same diameter as the drain pipe beneath it. To connect a no-hub drain, you need a no-hub connector. This is essentially a short wide section of pipe that slips over both the end of the drain and the end of the drain pipe, connecting them together. O-clamps are often used to tighten the grip of the connector on the pipes.
Installation and Removal
Hub drains are sometimes more difficult to install than no-hub drains. Soldering requires a lot of work, and access to specialized equipment like an acetylene torch. Any kind of hub drain requires extra room to remove. This is because it needs room to slide all the way to the end of the drain pipe before it can be removed. A no-hub connector can simply be loosened and slid down the drain pipe, allowing you to simply lift the drain right off of the pipe. If you have little available room, go with a no-hub drain.
On the other hand, some reserve no-hub couplings only for above-ground work, and require hub couplings if the joint is going to be underground. All the parts of hub couplings are braced strongly against each other. No-hub couplings are not so strongly braced, as only the connector braces the pipes, and each end of the joint is free to exert pressure on that coupling in different directions. If you are installing the drain directly into the ground, or if you believe it will experience a lot of force, then use a hub drain.
In general, there is little practical difference between hub drains and no-hub drains. Use whichever is most convenient for you. No-hub drains are the most commonly used type, according to "Plumbing Engineer" magazine.