The topic of today's tutorial is how to convert copper water pipes to PEX and then install a Delta R10000 mixer valve, bath spout and shower adapter.
The bathroom I'm using for this demo has a tub and shower combination, but this process can also be applied to a shower only.
How to install PEX water lines and a mixing valve: step-by-step instructions
In this step-by-step guide, I will first convert from 1/2" copper water pipe to Type B PEX using SharkBite couplings. PEX-B is an amazing product and very forgiving making it ideal for DIYers.
Once the new plumbing is in place I will walk you through the process of installing what I believe to be the best mixing valve on the market - the Delta R10000. This component has stood the test of time, but if you ever have a problem with your cartridge valve or require parts they are readily available.
Would you rather watch than read? Watch this 20 minute video.
DISCLAIMER: This video and description contains affiliate links, which means I will earn a small commission if you click on any of the product links.
How to Install PEX Water Lines and a Mixing Valve: Supplies, Tools, and Cost
deliveries
- Delta R10000 valve body(used for this installation)
- Delta R10000 valve body with PEX adapters and pool outlet already integrated(I discovered this product later, but it really is perfect for this project)
- ½ inch PEX-B
- of ½ inch SharkBite couplings (for copper to PEX transition)
- two 90 degree elbows for PEX
- 1 ¼ inch deck screws
- Teflonband
- pipe glue
- 2×4 and 1×6 pieces for the support blocks
Tool
- tape measure
- shocking driver
- pipe cutter
- deburring tool
- emery cloth
- Laser (optional)
Cost
I spent $314 on the Delta R10000 Mixing Valve and accessories.
How to Install PEX Water Lines and a Mixing Valve - Adding Block Supports
Before I get into the plumbing, I'll add some blocks between the studs to support the showerhead elbow, mixer valve, and tub spout.
This isn't a complicated task, but I want to do this work carefully so the supports land in exactly the right places.
I'll start with a few measurements. Here are three critical measures and one of them is constant.
The constant dimension is the distance from the bolt on the back wall to the center of the drain. We want everything to line up perfectly with the center of the drain. In my case it is 14 ½ inches.
Next I will measure and mark the height of the support blocks for the shower arm and tub spout.
Shower arm support block
I'm going to use a two by four to make my support block for the shower arm and cut it to the spacing between the studs.
I want the center of the shower arm to be 80 inches off the floor, but my tape measure only goes to the two by four at the bottom of the frame.
To figure out the position of the top of the block, I need to subtract the height of the two by four at the base of the frame (1½ inches) and add the distance the arm will sit from the top of the block. block (three quarters of an inch).
80 - 1.5 + 0.75 = 79.25 inches
I will mark the 79 ¼ inch height on both studs to indicate where to align the top of the block.
However, the block must be offset within the wall cavity. The shower arm is 1 ¼ inch deep and I would like it to recess slightly into the finished surface of the wall. I mount it in the area above the frame where there will be a half inch of drywall. So I'm going to stick the block three quarters of an inch back into the wall cavity.
Before screwing the block into place, it's a good idea to do an eye test. Just tap the block, hold the shower arm against it, and look at it from the side to see if it's lined up correctly. It should sit within a quarter inch of the surface of the finished drywall.
The positioning looks good, so I turn two screws per side to attach the block to the studs.
Mixing valve support block
Since I have a tub/shower combo, I will place my Delta R10000 mixer valve 30 inches off the floor as a person sitting in the tub needs access to it. If this was just a shower I would place it 48 inches off the floor.

The mixing valve must be placed on the wall so that its outer surface is flush with the frame. The thickness of the Delta R10000 from the outer panel to the back of the mounting flange is approximately 2.8 inches, let's say 2 ¾ inches.

My acrylic frame sits right against the studs. I don't have debris like with tile so almost all of the mixing valve sits in the wall cavity. That means I won't have room for a 2 x 6 block; I'm going to use a 1 x 6 instead.
Due to the thinness, I have chosen a wood that is slightly denser than pine and will build it fully into the wall cavity.
Holding block for bathtub spout
I want the spout of my tub faucet to be 4 ¼ inches above the surface of the tub. I also want the installation to be sturdier so I notched the top of the support block I made from a two by four piece. That way the heel elbow sits in the notch and gives me more surface area to hold on to.

I mounted the block on the tub spout flush with the front of the studs and the bottom of the notch 4 ¼" above the top of the tub.
How to Install PEX Water Lines and a Mixing Valve: Transitioning from Copper Lines
I will be replacing my copper colored tub and shower water pipes with PEX-B with SharkBite connectors. I chose these materials because this is a DIY project. Both the SharkBite and PEX-B couplings are easy to use, making them a practical option for DIYers.
NOTE: If you are familiar with soldering copper tubing, you should probably leave the copper tubing in place since copper is the strongest material for water tubing.
I will be converting my 1/2" copper pipe to 1/2" PEX-B using 1/2" SharkBite couplers made specifically for this purpose.

The small white insert on one end of the coupler is rated for PEX.

The PEX sits on the inside of the connector giving it a bit more rigidity. The O-ring, the critical part in a SharkBite fitting, helps the PEX maintain a tight seal.
NOTE: I had previously cut and capped the copper plumbing to keep the water in the house. Now that I'm going to trim them further and move on to PEX, I need to turn the water off.
Some people have doubts about the longevity of these SharkBite connectors. Since I have easy access to it in the crawlspace, I'm not worried. If I ever have to wait for her, it won't be hard.
Below, in the crawl space, the incoming water lines are as expected: the cold water line on the right and the hot water line on the left.
I'm going to cut the lines about 4 inches above the curve.
TIP: If the copper line is barely cut, allow the water to drain before fully disconnecting. If your main water line happens to not be shut off, this is your indicator and also prevents massive water intrusion.
After I cut my copper water lines I'm going to strip them off with a deburring tool and some emery cloth. Any burrs left on the pipe can damage the o-ring on SharkBite fittings, so do not skip this step.
I ran the 5 foot lengths of PEX from the bathroom and marked both the copper tubing and the PEX (blue for cold and red for hot) so I know how far each of the lines needed to be inserted into the coupler (0 .95 inches per line). Then I simply push the lines into the holder up to the mark.

NOTE: As you begin to insert the tubing into the fitting, you will feel some resistance as the tubing begins to hit the o-ring. Push past this resistance to fully insert the tubing. Not going to full depth is probably the main cause of leaks on SharkBites.
How to Install PEX Water Lines and a Mixing Valve: Valve Assembly
To set up my Delta R10000 mixing valve I'll just use threaded adapters with some teflon tape and pipe dope, but you can solder PEX adapters. Don't use 90 degree bends here; You will have a hard time squeezing and orienting them.
PRO TIP: Better yet, Delta makes aValve with integrated PEX fittings and tub spout installation already welded. This would have saved me the trouble of threading in the PEX fittings, which I discuss in the next section. It would also have given me a less restrictive route to my tub spout. (Thanks to our viewers for this pro tip!)

After tightening all the adapters, I crimp the PEX for the incoming hot and cold water, tub spout and shower arm and check everything with a go/no-go indicator.

With the PEX crimped to the mixer valve I'm ready to mount it to the support block.
I'm going to use a laser to mark the center point of the valve as I screw it in. (A laser is a very useful tool for jobs like this. PleaseVisit our Amazon store for a decent quality laser, good for DIY, it costs about $100).
The coordinates of the cross are my desired height (in this case 30 inches) and the center point of the drain (in this case 14 ½ inches from the back wall).

Now that the X marks the spot, all I have to do is line up the center of the valve (where the handle will attach) and attach it to the block with screws. I use 1 ¼ inch deck screws for this.
TIP: When securing the valve, make sure it is level. If you are using a laser, the horizontal beam is an easy reference for this.
How to install PEX water lines and a mixing valve: Assembling the shower arm and connecting the PEX
The shower head was a little low before, so I'm going to position the new shower arm a little higher, 80 inches off the floor.
My laser conveniently indicates the center point of the shower arm relative to the drain and I've already marked the height of the arm on the support block I installed previously.
After the shower arm is attached to the block, I cut the PEX to length and crimp it into the arm.


My final step here is to check everything with a Go/No-Go indicator.
To install PEX water lines and a mixing valve: Install the bathtub spout and connect the PEX
For the tub spout I use a copper pipe fitting, which is a piece of pipe with an elbow. I will eventually mount a delta adapter to the stub; Finally, the bath spout is screwed onto this.
NOTE: I used 1/2 inch PEX for the tub drip and spout, but it might have been better to use 3 liters which would have resulted in less restriction on water flow. Ideally I would use copper for the entire drop but I didn't want to deal with soldering, I installed PEX from the valve to the spout.The ideal solutionhere is the only thing to getMixing valve Delta R10000 with PEX adapters and already integrated bath tube downpipe.
To get started I need to cut the PEX that feeds the tub spout. I will show the stub to the PEX to get this measurement; then I will bookmark it.

After cutting the PEX, I crimp the stub to the tub spout and check it with my go/no-go gauge.
Now attach the tub spout fitting to the support block. I used five screws for this. Bulletproof!
The final step in roughing the pipes is to connect the incoming hot and cold water lines to the mixing valve. This is a simple matter of cutting the PEX and crimping it at a 90 degree angle. I find it easiest to start with the shortest horizontal piece and insert the angle connector first. The vertical piece, which is longer, is slightly more forgiving.

How to Install PEX Water Pipes and a Mixing Valve - Conclusion
There are many steps involved in replacing your copper water lines with PEX and installing a mixing valve, but it's not particularly difficult. With a little patience, care, and the right tools, it's an affordable DIY project that will save you tons of money.
Related tutorials
- How to Install a Delta Custom 400 Series Hull and Frame(written tutorial with video links)
- How to install a Delta bathtub spout(Video)
For complete bathroom renovation
Iscomprehensive bathroom reformfrom demolition to installing towel rails is available on YouTube.
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