One of my favorite features of my Promaster conversion camper (Miles Van Camper) is the wet bath with a shower and toilet. For many people this is just wasted space and they prefer using showers at campgrounds or having a gym membership for showering. For others having some sort of toilet than can be tucked away under a bench when not in use is plenty and others can’t imagine using a toilet in a van at all and prefer to use bathrooms “wherever” they are since they are so plentiful. For us, a hot water shower and a toilet in the van is a necessity. I hate the idea of having to leave the van to take a leak – particularly in the middle of the night. Also, my (amazing) girlfriend has the world’s tiniest bladder and needs to pee all the time (many times a night), so she wouldn’t even consider not having a toilet. In any case, one of the best things about building a DIY camper van is that you can design it for your personal preferences and how you’ll be using it!
Before I get into how I built my wet bath, I’ll point out that I have a list of all the parts I used on my build outside of things you can easily get at any hardware store.
You might also be interested in another post that details all my plumbing including a PDF diagram.
I started by building a frame that the 32″ long by 24″ wide shower pan sits on. The frame itself is slightly longer (33-1/4) to allow the walls to fit into a “gap” that goes below the shower pan (see illustration below).
I wanted the “Hepvo trap” that I used on the shower drain to be inside the van instead of underneath it. This special kind of trap provides the utility of a traditional “p-trap” – preventing odors from escaping from the grey tank – but can be installed horizontally to save space and also has a mechanism that prevents water from the tank from back flowing into the shower pan. If needed, I can access this trap/plumbing by pulling off a “panel” covering front of this shower pan frame. You can see how the frame is elevated off the van floor a bit as well as the access from the front in the photos below. At the same time, I wanted the shower pan as low to the floor as possible so that I didn’t diminish the available standing room in the shower. So, I put this frame directly onto the van floor versus on top of the plywood subfloor. Therefore the subfloor sort of goes around this frame. Every 3/4″ of an inch matters in a van! I also used Noico noise deadener below the shower pan.
I used various wooden furring strips cut to a variety of “depths” which are screwed onto the van walls at the “back” of the shower (the area just behind the slider door). These were necessary to “even out” the van wall so that the area where the pillar is – just behind the slider door – that “juts out” would be the same as the area directly “behind” it toward the rear of the van. However, I wanted to keep the natural “curve” of the van walls as they go up vertically. So, this process of having wood furring strips was a complicated task since there are so many contours and “layers” to this part of the van.
Once the back wall “framing” (furring strips) was completed, I cut a piece of 1/8″ plywood to be used for this back wall and screwed into into the van/furring strips. The 1/8″ plywood was flexible enough to conform to the curve of the van. Finally, I glued 1/16″ white plastic material to the back wall’s plywood using FRP adhesive. I have included a photo of the label of this material below – it’s called “Plas-Tex waterproof wall panel” and is made by Parkland Plastics. I bought it at the Home Depot. It’s thinner than standard FRP and less glossy as well.
The forward and rear walls are framed with 2″ x 4″ and 2″ x 2″ lumber. The vertical framing is attached to the van floor and upper metal “ribs” on the van with metal angle brackets and is also screwed into the shower pan frame. The horizontal framing is fastened to the vertical pieces in several places. This created a 2″ cavity in the walls which was necessary on the front wall for electrical wiring/boxes and the panels for the battery monitor, inverter and tank monitors. On the rear wall, the cavity is used for the hot and cold water lines and shower valve.
The forward and rear wall frames were then covered with 1/2″ plywood which also conformed to the curve of the back wall along their sides. This plywood wall goes down into the “gap” between the wall’s framing and the shower pan itself (see illustration below). The same 1/16″ white plastic material was glued onto these plywood walls and also goes “below” the shower pan into the “gap”. Finally the roughly 1/16″ joints between the shower pan and the walls and all the vertical gaps between the back and side walls were sealed with white silicone caulking.
The project wrapped up by installing the “disappearing” shower door (details my recommended product page) which was a very straight forward and simple process. I also added various trim pieces and the front “panel” below the shower pan for accessing the plumbing.
Eventually I also installed the “other side” of the walls which face front toward the cab and face back toward the back doors.
The toilet I used is a Thetford Curve cassette toilet. I utilized the mounting plate that is sold specifically for that purpose. The plate is secured to the shower pan (as far back toward the rear as possible to make room for standing in front when showering) using stainless steel screws. The toilet latches into the mounting plate and can be easily removed from the wet bath area to make more space or to empty.
Our experience with this cassette toilet has been very positive. The primary benefit of a “cassette” toilet is that it eliminates the need for a “black tank” that normally stores sewage waste. This is typically separate from your “grey tank” which stores waste water from the sink/showers, etc. in an RV. Black tanks are typically drained with what is often referred to as a “stinky slinky” – a 3″ sewer hose you connect from your rig’s black tank to a sewer line at an RV park or campground when emptying your tanks. This is no fun.
In contrast, a cassette toilet uses a removable “cassette” as the black tank. On my particular toilet, the top portion is a fresh water tank has water for flushing (there’s an electric pump that dispenses water around the toilet bowel when needed) and the bottom portion is the “cassette” or the tank that holds the waste. When it’s full (there’s an indicator on the front), you simply pull of the “top” water tank, set it aside, and then detach the bottom (cassette) to empty directly into whatever you’re dumping into. This eliminate the “stinky slinky” and is considerably more flexible. Not only can you you can dump into a standard sewer, but you can also use things like a porta-pot or even a standard toilet at a gas station. To be fair, dumping the cassette is no fun either, but, in my opinion, it’s considerably better than dealing with a black tank.
We’ve used this toilet extensively for both “number one” and “number two” and, as long as we use the right chemicals and leave a little fresh water from the flushing mechanism over the top of the “flap” that opens and closes to let whatever waste is in the bowl down into the tank, we don’t ever smell the tank!
Also in the wet bath is a soap dispenser hanging on the wall and a small mirror with a shelf on the front wall onto which the toilet paper hanger is mounted.