How to Install Rough in Plumbing for a Bathroom, Part 2

What You'll Need
Copper Piping
PVC Drain Pipe
Propane Torch
Tube Cutter
Hack Saw
Tape Measure
Plumber's Tape
Pipe Flux
PVC Glue
PVC Cleaner
2 by 4 Lumber

In Part 1 of this series, you created the initial rough plumbing plan and laid out the pipes for your bathroom renovation. In Part 2, you can turn your attention to the tub and shower installation. This is not something that you should take lightly, but a challenging DIY project that must be done in a certain way to adhere to your local codes. With the rough plumbing laid out, starting with the tub is important as the first step as you need to line up the vent pipes with the other fixtures. Also, since the tub is the largest piece to install, it is much easier to do it first rather than last. 

Step 1: Build Frame for Tub

Once the rough plumbing has been taken care of you will need to have a frame built to slip the tub into. This frame is built from 2 by 4 lumber and takes the shape of the tub, or a rectangular box. Attach a ledger board just below where the lip of the tub will go; some screw directly into the wall studs. When building the frame, make sure that you have approximately 1/8-inch to ¼-inch extra space all the way around the frame. This will allow for any adjustments that you need to make in case the measurements are wrong or the floor is not level.

Step 2: Install P-Trap and Drainpipe

Using the PVC pipe, attach the P-Trap to the drainpipe and install in the area directly underneath where the tub drain will go. The P-Trap should be level with the finished floor height. 

Step 3: Assemble Drain and Overflow on Tub

Once the P-Trap is installed onto the drain in the floor, you can then assemble the drainpipe and the overflow to the tub assembly. Dry fit these so that you can make any necessary cuts and adjustments. After they are measured, then cut with a hacksaw, and assemble them. Use a small amount of PVC glue and slide the pipes together into the couplings. 

Step 4: Slide Tub into Position

Once the assembly is on the tub, you can then lift the tub and carefully slide it into position. Make sure that the drainpipe from the tub slides into the P-Trap assembly on the floor. After it is leveled off you can then nail it to the ledger boards and floor through the flanges on the tub. 

Step 5: Attach Water Supply Pipes and Faucet

Using the rough plumbing for the supply lines (they are the copper lines) you can then begin to install the faucet for the tub and shower. Use the tube cutter to cut the pipes to length and attach with the solder and propane torch. Line the pipes up with the tub faucet, or the enclosure if you are using one. You will only need one supply pipe to the shower assembly and it should end with a threaded head. 

Step 6: Have Inspection

Once the tub has been roughed in you will need to have an inspection done before moving on. If anything is wrong up to this point you it is easier to make changes now rather than after the entire bathroom is complete.