Introduction: Shower Valve Replacement - Brass Rough-In, Copper Soldering, and PEX Tips

By Home Repair Tutor
About: We love home improvement and enjoy sharing tips on YouTube and Home Repair Tutor. Everything we do is self taught. Over the last 12 years we've bought and rehabbed several rental homes in Pittsburgh. Sometim…

Shower valve replacement doesn’t have to be painful.

In today’s tutorial we share step-by-step how to install a new American Standard mixing valve. You’ll see how to solder copper to the brass valve and how to use PEX to make this project a lot easier. In the end you’ll feel way more confident doing this yourself. Let’s dive it!!

Here are the supplies you need

  • MAP-Pro Gas ($15)
  • TS8000 Trigger Start ($39)
  • Plumbing Solder Kit ($17)
  • Tube and Fitting Brush ($10)
  • Deburring Tool ($10)
  • Emery Cloth ($10)
  • Pipe Auto Cut Tool for 1/2″ Copper ($17)
  • Pipe Auto Cut Tool for 3/4″ Copper ($21)
  • Standard Mixing Valve ($50-$90)
  • Ear Elbow for Shower Arm ($8)
  • Crimping Tool ($60)
  • Rings for 1/2″ PEX ($7 for 25)
  • Degree Copper Elbows for 1/2″ Pipe ($7 for 5)
  • Standard Quintin Shower Trim Kit ($190)
  • Extinguisher (FREE…You Should Have One)
  • Barbed PEX Adapter for 1/2″ Copper ($1)

Step 1: Watch Our Step-by-Step Video

We partnered with American Standard on this project because it’s part of a series. Our goal is to show you how to remodel a small bathroom.

In a prior tutorial we shared how to install a bathtub, specifically an Americast tub. After the tub is installed the next step is adding the shower valve. Watch our video for the complete step-by-step instructions…

Step 2: Center the Shower Valve

First things first, find the center location of the tub.

In this bathroom that was 14.5 inches from the stud on the exterior wall.

Follow your local plumbing codes to determine

  1. Shower Valve Height
  2. Tub Spout Height from the Tub
  3. Shower Head Height

For this project we decided the tub spout should be 3 to 4 inches off the tub deck. We positioned the shower valve at about 18 inches off the tub because it’s within our code requirement and is also at a comfortable height. The shower head height was set to 71 inches above the tub deck. We wanted it to be just above the top of the finished shower niche.

Step 3: Solder Copper Pipe to Shower Valve

Once you determine the location of the shower valve, tub spout, and shower head you’ll need to cut the pipes to size.

Autocut tools are great for this because they’re quick and painless. Cut all the copper to size, clean the edges with emery cloth or a brush, and debur the pipe with a deburring tool.

Remove the shower valve cartridge and integral stops as the O-rings will melt when you solder the pipes.

Dry fit all the pipes to ensure they fit properly. Apply solder to the pipes and inside the fittings. MAP gas is the best for this project. It quickly heats up the copper and brass. Evenly heat the copper/brass fittings.

Then dab the fitting with solder. When the solder starts to melt apply it to the fitting on all sides. Wipe away excess solder with a rag.

Our video has more soldering tips. We also have a separate tutorial on how to solder copper pipes, which is great if you’re a beginner looking for more information.

Step 4: Add PEX to the Copper

PEX makes shower valve installation a lot simpler.

You might be asking “why didn’t they use PEX for everything?” Copper makes it easier to position the pipes plumb, or vertical, in tight bathroom walls. You’ll see in the video that we check for plumbness using a level.

PEX can bend. And as a result this can create issues with positioning the tub spout and shower head. But you could use PEX for all the connections except the tub spout. We still recommend using copper for that.

Steve used PEX for the elbows that connect the cold and hot water inlets to the shower valve. You’ll need a crimping tool, crimp rings, and barbed copper fittings for PEX.

PEX cuts down on soldering inside the wall. This in turn reduces the likelihood of burning down your house. Our video shares tips for using PEX and we also have a separate tutorial that goes into more detail.

Step 5: Setting the Shower Valve Depth

Shower valves usually come with a plaster guard.

This shows you how far the the shower valve should stick out from the wall. In this example we needed the finished wall to be inside the plaster guard width. We positioned a piece of 1/2″ OSB inside the stud wall. And this bumped out the plaster guard to the right depth.

Secure the shower valve using galvanized screws. And double check that the tub spout is 3 to 4 inches from tub deck and centered on the tub drain. In addition, check that the shower head drop elbow is plumb and centered on the tub drain.

Once this is done you’re finished with the shower valve. The final step is to replace the cartridge and stops, add stoppers to the drop elbow & tub spout, and pressurize the system.

Check for water leaks and if there are none you’re good to go.

We hoped you liked this tutorial.

If you have any questions ask in the comments.

We'd be happy to help.

Jeff