When replacing a shower drain assembly, the water supply to the bathroom should be turned off and all pipeworks surveyed prior to beginning any repair work. The use of specialized tools, such as a pipe cutter or channel locks, may be required, depending on the type of pipes used in the home, and their condition and age. Once removal of the old assembly has been completed, these pieces should be reserved for use as a guide when buying and installing a new assembly.
The first key in replacing a shower drain assembly is to turn off the water supply to the bathroom where the repairs will take place. This can be accomplished by shutting off the water supply to the one room in question. If the home is designed in such a way that no separate shut off exists, then the main water supply lines to the home will need to be turned off. This prevents any leaking from occurring while the individual parts of the assembly are being removed, and will not compromise the integrity of any new materials or plumber's putty put into place.
The second key in this type of repair work is to fully survey the situation and all parts involved before beginning any removal. This often requires viewing the drain pipe assembly from an open access hatch cut in a wall behind the pipe location, or viewing the pipes through a crawl space. Modern homes are typically built using PVC piping, which is durable, long lasting, and can be cut through using a hacksaw. Older homes typically contain copper or galvanized piping, which require the use of a pipe cutter or a reciprocating saw, respectively. It is usually best to have all necessary tools on hand prior to beginning the removal of the shower drain assembly.
To begin the repair work, most of the shower drain assembly can be removed from above. The drain strainer is usually attached by means of two screws, with either a flat head or Philips design, which can be twisted out and set aside before removing the strainer. The strainer body is located directly below the strainer, and should be held in place by plumber's putty. If the putty is old and decaying, this piece may be twisted out by hand. If the putty continues to hold strong, channel locks can be inserted into the opening and tightened, before twisting the piece out in a cork-like fashion.
The drain body sits below the strainer body and is separated from this piece by a rubber gasket. This gasket acts as a seal between the shower pan and the drain body to prevent water seepage into the sub-floor of the bathroom. The drain body can be pushed to the side slightly to reveal the gasket, which may then be lifted away by hand. If the drain body does not provide sufficient movement, the gasket can be taken off from below with the removal of the drain body.
The drain body is typically too large to be removed from above, and should be securely fastened to the permanent drain pipe below. Depending on the type of piping contained within the house, the drain body can be cut away from the drain pipe. When reassembling this portion of the shower drain assembly, a PVC collar should be attached to the exposed end of the drain pipe to create a tight and secure fit with the new drain body.
A complete shower drain assembly may be purchased as a kit from a local home improvement store or through Internet ordering. It is often beneficial to keep the old parts until the new installation is complete for reference. Not all kits are designed to fit showers universally, and the old assembly pieces may be used as a buying guide. Most kits also provide instructions for installing the new parts, though their installation should be identical, though in reverse, to removing the old assembly. If PVC replacement pieces are used, then plumber's putty, which is designed to work with porous, plastic surfaces, should be purchased to create a water tight seal around the strainer assembly and rubber gasket.