Plumbing a Master Bath Part 3 of 3

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A large bathroom has more plumbing fixtures and consumes more water than any other room in your house. For this reason, a master bath has special plumbing needs.

 

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Continue to Step 1

Overview

A large bathroom has more plumbing fixtures and consumes more water than any other room in your house. For this reason, a master bath has special plumbing needs. Frame bathroom “wet walls” with 2 x 6 studs, to provide plenty of room for running 3" pipes and fittings. If your bathroom includes a heavy whirlpool tub, you will likely need to strengthen the floor by installing “sister” joists alongside the existing floor joists underneath the tub. Check with your local codes.
For convenience, our project is divided into the following sequences:
• How to Install DWV Pipes for the Toilet & Sink
• How to Install DWV Pipes for the Tub & Shower
• How to Connect Drain Pipes to a Main Waste-Vent Stack
• How to Install the Water Supply Pipes
From: The Complete Guide to Plumbing, 978-1-58923-378-2

What You'll Need

Tools:

Hole saw
Circular saw
Solvent glue
Drill
Jigsaw

Materials:

Hole saw
Circular saw
Solvent glue
Drill
Jigsaw

 

Step 1

How to Connect Vent Pipes to a Main Waste-vent Stack

In the attic, cut into the main waste-vent stack and install a vent T-fitting, using banded couplings. The side outlet on the vent T should face the new 2" vent pipe running down to the bathroom. Attach a test T-fitting to the vent T. Note: If your stack is cast iron, make sure to adequately support it before cutting into it.


Step 2

How to Connect Vent Pipes to a Main Waste-vent Stack

Use elbows, vent T-fittings, reducers, and lengths of pipe as needed to link the new vent pipes to the test T-fitting on the main waste-vent stack. Vent pipes can be routed in many ways, but you should make sure the pipes have a slight downward angle to prevent moisture from collecting in the pipes. Support the pipes every 4 ft.


Step 3

How to Install the Water Supply Pipes

After shutting off the water, cut into existing supply pipes and install T-fittings for new branch lines. Notch out studs and run copper pipes to the toilet and sink locations. Use an elbow and female-threaded fitting to form the toilet stub-out. Once satisfied with the layout, solder the pipes in place.


Step 4

How to Install the Water Supply Pipes

Cut 1" x 4" high notches around the wall, and extend the supply pipes to the sink location. Install reducing T-fittings and female-threaded fittings for the sink faucet stub-outs. The stub-outs should be positioned about 18" above the floor, spaced 8" apart. Once satisfied with the layout, solder the joints, then insert 3⁄4" blocking behind the stub-outs and strap them in place.


Step 5

How to Install the Water Supply Pipes

Extend the water supply pipes to the bathtub and shower. In our project, we removed the subfloor and notched the joists to run 3⁄4" supply pipes from the sink to a whirlpool bathtub, then to the shower. At the bathtub, we used reducing T-fittings and elbows to create 1⁄2" risers for the tub faucet. Solder caps onto the risers; after the subfloor is replaced, the caps will be removed and replaced with shutoff valves.


Step 6

How to Install the Water Supply Pipes

At the shower location, use elbows to create vertical risers where the shower wet wall will be constructed. The risers should extend at least 6" above floor level. Support the risers with a 3⁄4" backer board attached between joists. Solder caps onto the risers. After the shower stall is constructed, the caps will be removed and replaced with shutoff valves.


 
 

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