This is sometimes an easy job, but in other cases it can prove to be one of the trickier plumbing repair jobs you will tackle. On an existing tub, gaining access to the overflow tube can be challenging, and the process for replacing the tube can vary greatly, depending on what type of drain pipes you have and how the fittings have been made. Chrome or plastic parts made with slip fittings can be relatively easy to replace, but if the fittings are soldered or solvent-glued, the process can be much more complicated than you’d expect. DIYers sometimes find themselves over their heads when trying to accomplish this project, so evaluate the situation carefully before you tackle it yourself.
Anatomy of a Bathtub Waste-and-Overflow Assembly
The waste-and-overflow unit is an L-shaped assembly that consists of a drain fitting that sets into the opening in the bottom of the tub, connecting to a short horizontal drain pipe that runs to a tee fitting. The top outlet on this tee connects to the vertical overflow tube that terminates at the overflow opening in the tub, while the bottom outlet on the tee runs to the bathtub’s drain trap and branch drain. There are several connections you will need to make when installing the assembly: the bathtub’s drain unit, the overflow cover plate, and the various fittings that connect the pipes.
Access Issues
Installing a new tub waste-and-overflow can be a bit of a project, so be prepared. If your bathroom is over an open basement or crawl space, you’ll be able to access the drain from underneath, which is easier. If you have a slab foundation there might be an access panel that allows you to work from behind the tub. If there isn’t one already there you may need to cut one in before you can get the old waste-and-overflow out and the new in. No matter which type of access you have, the steps are roughly the same.
Tools and Supplies You Will Need
The materials required to remove and replace a bathtub waste-and-overflow tube will depend on what types of pipes and fittings are present. You can buy individual parts for different parts of the overflow assembly, but it’s usually easiest to buy a complete assembly that includes the bathtub drain fitting, the overflow tube and cover plate, the tee fitting, and both the vertical overflow tube and horizontal drain arm connecting to the drain fitting. If you are installing a new tub, the manufacturer may supply the waste-and-overflow; if you are replacing the assembly on an existing tub, look for one that closely resembles the old one. Waste-and-overflow assemblies comes in several forms, including styles that include an integrated stopper assembly and lever. The style you choose is up to you. You may require some or all of the following:
Tub drain wrenchScrewdriversChannel-lock pliersBathtub drain and overflow kitHacksaw or tubing cutter (if needed)Plumber’s putty
Instructions
All of the following instructions will apply if you are replacing an overflow tube on an existing bathtub. If you are installing an overflow tube on a new bathtub for the first time, jump past the removal steps and begin with the installation steps.
Note: You may want to change the drain trap under the tub at this time. Since access is difficult, it may be easiest to replace this part at the same time you are working on the overflow assembly.
If necessary, cut the pieces to size. After cutting, dry-fit the pieces again to make sure the overflow tube and drain arm line up correctly. A waste-and-overflow using slip-joints is easy to line up because you can leave the washers and nuts loose while sliding everything into position. If necessary, extensions can be used on the tubular pipe to make the overflow tube longer. Depending on the type of kit you are using, making the connections may require simply slip fittings, in which slip nuts are tightened down with channel-lock pliers; or it may require using solvent glue to permanently weld the PVC joints. If you are making the connections with slip joints, secure the slip nuts loosely at this point. Thread the drain fitting into the threaded tailpiece of the drain arm, then tighten it down with a drain wrench. This works best if you have a helper hold the drain arm in place from below the tub as you tighten down the drain fitting from above. The plumber’s putty should slightly ooze out around the flange of the drain fitting as you tighten it.
