Home Improvement: How to Plumb a Bathtub Shower
Visions of old sitcoms flash through the memory as amateur plumbing projects are pondered. Water pipes springing leaks and the leaks springing leaks are worries that people carry that prevent them from tackling do-it-yourself plumbing projects. By just using a few easy steps, most home plumbing repairs can be successfully completed. Plumbing a bathtub shower can be a bit time consuming, but the work is not difficult to master.
Since the bathtub is already installed, you only need to worry about the shower.
The shower will use the same drain system as the bathtub. The water pipes are already available at the point where you need them. The only tricky part is getting access to the places where the new plumbing will be installed. If you do it right, you can plumb a shower into your bathtub without having to do any carpentry work beyond putting in a tub surround to protect the walls.
Decide if you want the shower head to be fixed in the wall or ceiling or have it on a hose.
If you want to take the cheap and easy way out, you can install a shower in your bathtub by just changing the spout. There is a product called a “Handshower Diverter Spout” that can be installed quickly. To install it, you need to grip the spout in the bathtub and twist it counterclockwise to unscrew it from the water pipe that supports it. If it is difficult to turn by hand, you can use a pipe wrench. Be careful not to be too robust because you do not want to damage the pipe it is screwed onto.
Set the old spout to the side and wipe off any grime from the water pipe.
Wrap Teflon tape around the threads or applied pipe dope. Screw the new spout with the diverter built in onto the threads of the pipe. Take care not to start it on an angle. This can ruin the threads and force you to do a lot more work or risk major leaks. Once the spout is tight on the pipe, turn on the water slowly. Pull up on the knob on top of the spout to shift the water into the diverter tube. Although the hose is not connected at this point, you can test the fitting and check for leaks.
Wrap Teflon tape around the threads on the on the diverter tube.
Screw the shower hose attachment onto the diverter tube until it is tight. Attach the brackets with screws to the wall above the tub spout to hold the shower hose in place. This will allow you to use it like a traditional shower head or remove it to use it as hose. Once the bracket is in place and the hose is resting in it, this installation is complete.
The other option for plumbing a bathtub shower is easiest if you are doing a major bathroom remodel.
Open up the access panel to the water lines that feed the bathtub faucets. If you are lucky, this is a door sized opening that will let you reach the height of the new shower head. In all probability, you will have to use a saw and remove some wall covering to have access to enough space inside the wall to install the new plumbing hardware.
In the bathroom, remove the tub spout by unscrewing counterclockwise.
Make sure that you have turned off the water supply to the bathtub before continuing. Remove the knobs from the faucets. Unscrew the covers on the faucets to loosen the faucet set from the tub wall.
Return to the wall opening.
Disconnect the water lines from the faucet set. Hopefully, this will only require you to unscrew the pipes from the faucets. If they are soldered in place, you will need to cut the lines an inch or so below the faucets to remove them. If you see that the new faucets will match exactly to fit the water lines, you may be able to heat the old faucets until the solder releases. Most people are not this lucky, or they choose not to solder the new faucets to the water lines.
Pull the old faucet set out of the wall when it is disconnected from the water.
Attach any adaptors that may be needed to connect the new faucets to the water lines. Unless your plumbing is extremely old, this really should be just a matter of disconnecting one faucet set and connecting the new one by screwing the lines to the fittings on the set. Use Teflon tape on the threads to help prevent leaks.
Return to the bathroom to continue the installation.
Measure the tube that will carry water from the faucet openings up to the shower head location. Mark this location on the wall. Use an appropriate size wood bit to drill a hole for the shower nozzle to extend through the wall.
Return to the back of the faucet set and install the riser from the faucets to the shower head.
This is usually just a matter of screwing the pipe into the opening on the faucet set. At the upper end of this tube will be another tube that will protrude through the wall for you to attach a shower head to.
In the bathroom, attach the faucet knobs after you screw the plates that cover the openings into place.
Screw the new tub spout into place. It will have the mechanism built into it that allows you divert the water to the shower head. This might be a faucet type of diverter or just a plunger that you pull up. Attach the plate to cover the opening in the wall where the shower head will be. Screw the shower head onto the fitting.
Turn the water on to the bathtub.
Turn on the faucets and bleed the air from the lines. Try diverting the water to the shower. Check all of the fittings for leaks and repair any that are found. Do the carpentry to repair the wall opening to complete the installation.
