Installing a New Shower Unit

What to Consider when Installing a New Shower Unit

By Mark J. Donovan

Installing a new shower unit is not for the faint of heart. It requires a great deal of planning and work. There are four stages to installing a new shower unit: framing the shower walls, roughing in the plumbing, installing the new shower unit, and finishing the plumbing. In regards to the actual plumbing of a new shower unit you should plan on hiring a plumber as most municipalities will not let a homeowner install their own plumbing.

Most new shower units and their associated plumbing fixtures can support various water pressures.

However make sure to ask the bath/shower supply store about this subject to ensure there are no specific issues with the particular type of shower unit you plan to install.

Similarly make sure you discuss water pressure and piping requirements with the plumber to ensure the right size supply and drain pipes are used for the new shower unit installation.

Shower Unit Mixing Valve Types

Bath/Shower Mixer: With this type of shower mixing valve unit the hose and spray are shared with a bath mixer faucet assembly and the water temperature can be adjusted through the bath mixer. This type of shower mixer unit is inexpensive and can be somewhat difficult to control the temperature.

Push-On Mixer Shower Unit Types: They work similar to the Bath/Shower mixer. The hose and spray components on the push-on mixer can be tied into the bath faucet tap and the water temperature can be adjusted via the faucet taps. Again, this type of mixer is relatively inexpensive and easy to install.

Installing a New Shower Unit

Manual Mixing Valve Unit Types: With this type of mixer unit, the hose and spray are an integral part of the wall unit and the cold and hot supplies are tied together via a single mixing valve.
The water temperature is adjusted via a screw or knob in the single mixing valve assembly. Manual mixing units are typically more expensive than the other types of mixing units previously mentioned.

Thermostatic Mixing Units: Again the hose and spray of this type of shower are an integral part of the wall unit. Similarly the hot and cold water lines are connected via a single mixing valve. What makes this type of mixing valve unit unique is that it has a built in thermostat with a stabilizer to auto-adjust the water temperature and to prevent scalding. This type of shower mixing unit is quite expensive.

Power showers incorporate a strong electric pump that enables easy modification of both the water temperature and pressure coming out of the hose and spray unit.

Electric showers are plumbed into the main cold water supply line and the water is heated electrically prior to it exiting the shower head.

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Electric shower units have several pros and cons but chief among them is that they need a very specific and consistent water pressure to ensure a stable water temperature exiting the shower head. Moreover, their control is limited. Either you can get higher temperatures at less pressure or cooler temperatures at higher pressure.

Actually Installing Shower Unit

When installing a new shower unit it is important to follow the rough plumbing instructions carefully. The shower drain, mixing valve, taps and shower head exit pipe must be perfectly located. If not, you’ll find yourself having to pull out the new shower unit and redoing the rough plumbing. Mark the required locations for the drain, mixing valves, taps and shower head exit pipe on the subfloor and wall studs to ensure they are installed in the right location. Also, make sure the rough plumbing pipes are blocked in tightly to prevent flexing or movement of the pipes when the taps are turned on and off. In addition, pressure testing of the supply line pipes should be done to ensure there are no leaks.

The shower pan, or tray, should be installed first when installing a new shower unit, unless the shower unit is a one piece. The shower walls should then be affixed to the walls studs and silicone caulk applied around all the seams. If you’re installing a single piece fiberglass shower unit make sure to fasten the shower to the wall studs with metal fastening brackets that slip over the shower wall flange and nail to the wall studs.

Once the shower tray and walls are installed, you can then move on to complete the finish plumbing. The finish plumbing involves installing the mixing valve/faucet handles, the shower drain, and the shower spray head and hoses.

Finally turn water on to the shower supply lines to complete the new shower unit installation. After turning the supply lines on check for any leaks. With any luck you’ll have a fully functional and leak free new shower.

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