Installing a Bathtub Shower Unit

How to Steps for Installing a Bathtub Shower Unit when Remodeling a Bathroom

By Mark J. Donovan

Installing a bathtub shower unit requires a combination of brawn and skill and should typically be done while the home is still in the rough framing stages. Though not extremely heavy, a bathtub shower unit is however large and bulky. Consequently the first two requirements associated with installing a bathtub shower unit are having a couple of strong backs and sufficiently wide enough door widths to bring the unit into the bathroom.

It is also important that there is adequate framing for supporting the weight of a bathtub shower unit.  Prior to actually installing a bathtub shower unit, make sure the local building inspector has examined the floor joists to make sure they are sized appropriately for carrying the weight of a full bathtub.

When installing a bathtub shower unit, begin by positioning the fiberglass bathtub shower unit into place within the wall studs. Make sure that the continue flange area of the bathtub shower unit rests against the wall studs on 2×4 supports.

To complete the rough-in stage of installing a bathtub shower unit, fasten the bathtub shower unit flanges to the wall studs with either nails or screws.

After installing a bathtub shower unit, the next step involves roughing in the plumbing around it. This includes the installation of the waste lines, including the trap, as well as the bathtub shower unit valve, and the hot and cold supply lines.

The first step in rough in the plumbing, after installing a bathtub shower unit, is to make the drain connections between the bathtub overflow and the bathtub drain itself.

Installing a bathtub shower unit.

The bathtub overflow piping should connect with the drain itself. The drain trap connection is made via a compression fitting that screws down tightly over the overflow assembly.

Once the waste lines have been connected, you can then move on to installing the hot and cold supply lines, as well as the bathtub shower unit mixing valve. In addition, you will need to assemble one additional pipe that extends above the mixing valve for the showerhead. Sweat a female fitting on top of the showerhead pipe so that a showerhead can be screwed onto it at a later point.

The final plumbing step in installing a bathtub shower unit is to sweat a small length of ½” copper pipe that extends below the mixing valve, for the bathtub spout. Sweat a male threaded fitting at the end of the pipe so that a bathtub spout can be screwed onto it later.

Once you have completed installing the bathtub shower unit and rough plumbing, you will need to have it inspected by your local building inspect. Upon passing its inspection, you can move onto the final two stages in the process of installing a bathtub shower unit.

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After completing the plumbing inspection, install moisture resistant drywall above and on the adjacent sides of the bathtub shower unit.

One useful tip is to nail a few small pieces of asphalt shingles along the wall studs above the bathtub shower unit flanges. This helps to prevent a bowed appearance on the finished drywall. After taping, mudding and sanding the drywall, apply silicone caulk around the bathtub shower unit seams to prevent any water penetration.

The final step in installing a bathtub shower unit is to install the shower head, bathtub spout, and handles. Make sure to use plumbers tape on the showerhead and spout to prevent any leaks.

For help on your bathroom remodeling project, see my Bathroom Remodeling Bid Sheet. The Bathroom Remodeling Bid Sheet provides a request for quote checklist section that you can provide to prospective bathroom remodeling contractors. It also includes a comprehensive bathroom remodeling cost breakdown table, in Microsoft Excel format, that allows the contractor to include his projected remodeling costs for every phase of the project.

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