Plumbing a Skoolie Conversion | Pex A verses Pex B
Feel free to jump ahead to the information you need.
We recently moved away from working on the front of the bus and began working on the bathroom. With some of the work already out of the way, the biggest project we face in this room is the shower. Before we could get to tiling, we needed to finish the plumbing. And we did!
It's exciting to finally have that out of the way so we can move on to building the shower itself. I am glad we took our time and made sure everything works because once we get that tile in...we're not going to be able to fix any problems behind the wall. Not without having to tear apart our shower at least. So hopefully no problems come up!
We did a lot of the main plumbing throughout the bus earlier this year which we’re thankful for. We already had the plumbing coming up into each room from the under-body storage that houses our water tanks. That meant finishing the bathroom plumbing could all be done from the inside while we avoid the rain!
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We did a lot of research trying to find how exactly we wanted to do the plumbing for our skoolie and what the best options for a moving vehicle are. We found that there were some popular options but pretty much everyone built their system differently.
Popular Plumbing Options
From what Matthew and I have seen, there are really three main options for plumbing a skoolie conversion. They are as follows:
PVC is definitely the easiest to use while copper is the hardest. Pex lands in the middle of that spectrum but is still easy to use.
Now, let me clarify something. Pex is not a brand. Pex is the type of material the tubing is made of. You can buy the Sharkbite brand or any generic brand. The Pex tubing we got for our build is from Apollo because that is what they had at Home Depot.
Why We Chose Pex
For us, this seemed like the best option for several reasons.
For starters, this system has great reviews and professionals love to use it. Using a trustworthy product is important to us, and we do feel like Pex is a trustworthy solution.
With it being used by professionals, I immediately expected the process to be difficult and therefore require a professional. That is definitely not the case. It is actually a super simple product to use. It doesn't need much skill or time to learn the process and we only needed a couple of tools.
Unlike Pex, copper takes a lot of skill and work to properly install. You have to solder them just right to get the connections to work. It just wasn't worth it to us to go this route. We were also worried that it would be too stiff of a system and wouldn't hold up well in a bus that's on the move all the time.
Another reason we went with Pex (specifically Pex Type A. More on this down below) is for the flexibility of it. Pex A is flexible and freeze-resistant, which makes us feel a lot better about having it in our skoolie.
PVC, as easy as it is to use, just can't give you the reliability that we needed. It doesn't do as well holding up to water pressure and the connections aren't the strongest.
These are just a few of the reasons we personally decided to go with Pex rather than PVC or copper. Things like your skill level, needs, and plumbing setup are going to be different for everyone. Those are all things to consider when determining which product or system you want to you.
Pex A Verses Pex B
To make things a little more confusing, there are two types of Pex and they have a lot of differences. Like I mentioned before, Pex is the material of the tubing and not a brand name. So type A and type B are totally different materials, not just a different assembly process.
Just about the only thing they have in common is their color options. You can get red and blue Pex to make it easy to keep track of your hot and cold lines, or simply get white.
We bought a large roll of Pex A and the store only had white available, which was totally fine. We just have to label each line so we don't mix them up!
This is the more flexible of the options which is one of the reasons we went with it over Pex B. With the bus constantly on the move, we wouldn't want to risk our plumbing getting pulled apart or shifting in a way that could cause problems. Also, we have our water tanks and therefore some plumbing under the bus, which means they're exposed to the cold. The flexibility of the Pex does well with temperature changes and makes us feel a lot better about it.
To install Pex A, you expand the Pex piping and quickly insert a fitting before it shrinks back down and creates a tight seal. I'll explain this in more detail here shortly.
To expand the Pex, you have to buy a Pex expander tool which costs around $100 for a basic one. You'll also need a Pex pipe cutter, though this is much cheaper. Since you need these tools, this is sometimes the more expensive route.
Only one of the hardware stores in our area carried Pex A and had the correct fittings. Unfortunately, it wasn't the closest one. Needless to say, it was a bit of a drive each time we realized we needed a different fitting.
This option is generally considered to be the easier of the two for homeowners to use and is found in more stores than Pex A is. Additionally, you won't need to buy a Pex expander tool for this type, which saves you a good chunk of change.
Pex B works a lot differently than Pex A does. To install a fitting to the Pex, you either use a barbed Sharkbite fitting or crimp metal rings to secure the Pex to the fitting. While both options are fairly easy, the barbed Sharkbite definitely takes the title of easiest to use since it requires no tools at all.
The downside to type B is that the Pex is much more rigid and the way the fittings are attached isn't as reliable as type A.
We hope to never have an issue with our plumbing, so we are taking every precaution we can. For us, that meant going with the more flexible and reliable Pex A.
Even though it cost a little more for tools and was harder to find, it was well worth it to us for the peace of mind and durability.
There are a lot of different fittings available for all your needs and based on which type of Pex you went with. You can pick and choose how you want to design your plumbing layout and what exactly your needs are.
Pex A Fittings
Since we went with Pex A, we needed the type of fittings that the Pex shrinks around. They come in plastic and metal options, though I'd recommend the plastic. The brand we used was Sharkbite, even though we didn't use the barbed "shark bite" style fittings like they are most known for since those are only for Pex B.
We used some elbows, tees, and a manifold much like the ones below.
The manifold piece we bought has one 3/4" inlet and four outlets that are 1/2". This is what we used to split off all the lines from the water source. Depending on your system, you may need more or less outlets.
Additionally, you will need some expander rings. These are also made of Pex and have a memory. They add extra strength to the connection point.
We used mostly plastic fittings for our plumbing. It was cheaper and the plastic options were easier to find. However, there are also brass fitting options available. We did end up using brass tees when we couldn't find the plastic option in the store.
Anywhere that the Pex tubing had to attach to a threaded connection point, we needed to use the brass fittings to get that thread. Places where you might need this would be the showerhead, shower valve, or sink faucets. These are the male and female brass adapters we used.
I have heard that the plastic fittings are the better option since brass tends to react to acidic water. With us traveling the country and always having different water sources, we don't want to risk messing up our plumbing work.
Once you get the connection done, it should look something like the photo below. The Pex tubing should have an expansion ring on the end and be pushed all the way onto the fitting.
Pex B Fittings
As I mentioned before, this type of Pex works a lot differently than Pex A. This means you'll need different fittings. Within the Pex B world, there are two types of fittings you can choose from.
If you go the standard Sharkbite route, your fittings are going to look like this.
To use this fitting, you simply push the Pex into the fitting and the little barbs inside hold the Pex in place. That's it. No tools or anything, which is why this method is so loved.
This type of fitting only comes in brass which means they will be a little more expensive. Because of the way that this fitting works, it is going to restrict the water flow at each connection since the inside of the fitting is smaller than the inside of the pipe. This isn't really an ideal situation, but may or may not be too big of a deal for your system.
The other route you can go with Pex B is crimping, which will have your connections looking like this.
These fittings will also be made of brass and the crimping rings are also metal. Of course, this approach will require you to buy a crimping tool.
How Does It Work?
Since we chose to use Pex A and believe this is the better of the two Pex options, this is the one I am going to explain fully.
There really is a lot of science that went into the making and functioning of Pex plumbing, and I don't understand it all.
Thankfully I don't need to and can still feel like a pro!
Pex A works by having a memory. This means that when you expand it, it will shrink back to its original size. So when you sneak a fitting in there real quick after expanding it, the Pex will shrink back around it and make a tight seal.
In short, here are the five steps it takes to make a Pex connection:
Cut your pex to length
Put an expansion ring on the end you are going to expand.
Pick your fitting (elbow, tee, etc.) and have it easily within reach.
Use the Pex expander tool to stretch out the Pex and expansion ring simultaneously.
Quickly slide the fitting inside the Pex and hold for at least 15 seconds.
Tips For Installing Pex A
Using Pex A is really simple, but there are a few things you can do to make the process go smoothly and get the best results.
Before you start expanding the Pex, make sure you have one of the expansion rings on. This needs to be expanded too and it must be on all the way. One side of the ring has a ridge on it which should butt up to the edge of the Pex when it is on all the way.
When expanding the Pex, rotate the expander tool a few times to ensure you are evenly expanding all sides of the Pex. If you get a fancy expansion tool like this DeWalt one, you won't have to do this step since the tool already does it for you.
Another thing to keep in mind is to make sure you push the fitting all the way in before the Pex shrinks. This will make a secure connection and tight seal that you won't get if the fitting isn't in all the way.
When you buy Pex, it typically comes coiled up, which means it naturally wants to stay curled up for a while. To straighten it out, just bend it in the opposite direction a little bit, but be careful not to get kinks in the line.
We also learned another way to do this a lot faster. Standing with your legs close together, run the pex through your legs from left to right. By forcing it to weave through your legs, you're reversing the curve and therefore straightening it.
Lastly, if you need to get your Pex back to its original size, you can use a heat gun! The heat will make the Pex shrink and become more malleable.
Common Mistakes and How To Fix Them
Our first time using Pex, there was one mistake that we made a couple of times and I'm sure you will make it at some point too. Sometimes after expanding the Pex, we wouldn't get it in all the way onto the fitting in time or would let go too soon and the Pex shrinks down in the wrong position. You want to have the tubing all the way on the fitting, so if it shrinks down while only halfway on, you'll need to redo it.
While it is easy to make this mistake, it is also thankfully really easy to fix. Using a knife or the Pex cutter, we were able to cut both the expansion ring and Pex and pull them off the fitting. If your Pex is cut to the exact length you need and you don't have spare Pex to work with, then cutting it off may not be the best option.
If that's the case, you can use a heat gun to warm the Pex up which will make it more malleable. You may be able to wiggle it off after softening it this way. You will need to expand the Pex again and redo the process, but it should work.
Another thing you can use the heat gun for is fixing kinks in the Pex line. When you heat up the Pex, it softens and will return to its original shape, mending the kink.
Tools and Equipment List
Now that I've convinced you to go with Pex A, I'm going to give you a list of all the things you're going to need. In the list below, I've included everything we used and some things you may choose to use. It was really hard for us to find this sort of information and find it in stores, so hopefully this makes your plumbing experience faster and easier!
Matthew and I are really glad we went with Pex A for all the plumbing in our skoolie. We found it to be the best option for both durability and ease of use. We were surprised by how easy and fun it was to install!
It would have been nice if we could buy red and blue Pex to keep our hot and cold lines color-coded, but we did just fine with the white.
I'd encourage you to go for it and use Pex A. We really loved our experience with it and wouldn't want to do it any other way.