Hello glorious folks of the forums!
I know this has been discussed, even debated, multiple times before on this forum. I know there are people out there who have converted their rear bath layout to a mid bath. There are also many who have wanted to, but decided against it. I believe that I understand the main issues with this project: window, vent, and hatch locations, and blackwater tank relocation.
A mid bathroom is tricky to fit into the window, vent, and hatch layout - which you really don't want to have to change. It seems silly to have a window in the shower (especially when your windows are these pesky 1968
leak-fests). The bathroom cannot be too wide because of running into the ceiling vents. You are potentially rendering an outside door/hatch useless, which you'd like to avoid. A mid bath would also not line up with the ceiling plumbing vent holes from a rear bath layout. Also note that the bathroom now sits on the wheel wells.
Now for the tanks. A mid bath would sit above the axels so one must weld (or I've also seen rivet) a new tank holding compartment to the frame that does not interfere with the axels. Also the drain/valve must be accessible for dumping said black water tank. Many who have done this conversion avoid the black water tank relocation issue by using a composting toilet.
If any of that information is inaccurate or I am missing significant concerns with the rear to mid bath conversion please let me know! Also, I am planning on using a composting toilet but have been told installing a black water system would be highly valuable for resale purposes.
Now for my questions. My 1968
Overlander (originally a rear bath) has a tank compartment in the very rear of the trailer that drops 4-5" below the belly pan. This was originally for the black water tank and no grey water system was in place. My plan is to keep this compartment and have my grey water tank there in the back. It would no longer be directly under the bathroom, but since it just collects shower and sink water (no solid waste) I don't foresee that being an issue (as in, there will still be enough drop in the pipes to let gravity do its work). Does this seem true?
The axels sit below the belly pan. So the order is road, axels, belly pan, trailer frame, subfloor. My frame is 5" tall (bottom of frame to bottom of subfloor). They certainly make tanks narrow enough to fit here (VTS has 4" tanks). So really I should be able to weld or rivet on some metal straps or an entire compartment to hold the tank. My concerns here are 1. future access, 2. insulation, and 3. emptying the tank. First a general plumbing question: must your toilet sit directly on top of the black water tank? I assume it does.
1. Is it super important to be able to access/replace the water tanks (without ripping out the bathroom and subfloor)? Do I need to make a compartment that can open?
2. My original black water tank had about 2" foam insulation around it plus a tube from the furnace to keep it from freezing. I live in California with no plans to camp (at least long term) in any freezing locations. How important is insulation around a black water tank (and a grey water tank while we're at it)?
3. The drain for this tank setup would be located ~1ft away from the side of the trailer, on the other side of the main solid chassis rail and actually in between the wheels. It would be inconvenient for sure to connect the hose to empty the tank - but doable (at least it seems it would be doable to me). What are the concerns with this besides inconvenience? Has anyone come up with a way to make the drain more accessible?
Thank you thank you thank you for your help! I would truly be lost without the forums