Campervan Conversion - Part 4 - Water Tanks & Shower Room Framing

In this post, we're initially looking at the water requirements for the van build.

We've bought a 75 litre tank for fresh water and a 85 litre tank for waste water, both of which will be installed inside the van.   Many people fit at least the waste tank under the vehicle, i.e. underslung from the floor beams and effectively located outside, but I wanted everything to be mounted inside the van and easily accessible for installation, piping & maintenance etc.

upright 85 litre and flat 75 litre tanks ...

There will also be a small hot water tank to design, build and install at some time in the future but that's not an urgent requirement - I can come back to it later when I've eventually figured out exactly how to provide a hot water system.  For now, we'll just concentrate on the main tanks, and I'm including the shower tray here because it's a deep unit and can hold more than 40 litres (see Post 3 in the series). 

The sink and shower greywater will collect in the 85 litre upright tank which sits on the floor up against the LH rear wheelarch.  The flat 75 litre fresh water tank is mounted directly above it.   This configuration minimises the amount of space required for the tank cabinet.  The top of the waste tank is low enough that the kitchen sink waste will flow to it under gravity, although water from the shower tray at floor level will be pumped into it.

Both tanks are MDPE proprietary units, each including a large screw cap on the top surface and pre-fitted with a single 3/4" BSP outlet insert at a lower corner.  There'll be valves fitted on here with couplings for drain hoses.   

I'll need to drill and add further connections at the top of the waste tank, for the waste flows from the sink and shower, and also for a vent pipe which will be routed outside the vehicle up near the roofline, so there'll be no nasty smells inside the van.

There are no further connections needed in the fresh water tank except for a small vent valve in the access cap to allow the air to enter as water flows out.  I'll configure the outlet pipework with a short pipe section upstream of a drain valve - a pressure-regulated pump for the sink taps and showerhead can be fed from a tee in this spool piece.

I've already received the ball valves and many of the other pipe fittings, although there's still a few more bits & pieces to procure.

tank fittings ...

I've built an enclosed cabinet structure to hold the tanks, mounted from the LH wall and floor of the van.  I used only lengths of 18x44 mm and 18x28 mm planed timbers.  The cabinet vertical corner posts are formed by gluing and screwing two 18x44 timbers together to form odd-leg angles.  

It took some time to construct this cabinet, and it's heavily cross-braced because the centre of the 75 litre fresh tank is 750 mm up from the floor, and of course the vehicle moves so there are dynamic forces to consider.  

tank cabinet over the wheelarch ...

If this was a paid-work project in which I was designing the tank supports, then I'd likely assume the tanks could be subjected simultaneously to 0.5g in both the lateral and longitudinal directions plus 1.5g in the vertical direction, so when the tanks are full there are some large forces for the structure to handle.  Imagine a heavy person sitting at that location and being thrown around when the vehicle corners and rides out the bumps in the road, and that's indicative of the strength of the structure required.

Anyway, the tank cabinet is just about finished, although I need to add pieces which will actually hold the tanks in their fixed positions.  The cabinet framing will be covered with plywood on the side and front end, which will further stiffen the structure.  

The top will be covered by the kitchen worktop, with a hinged cover to access the fresh water filling cap, and I've already started building the kitchen unit framing out forwards from the tank cabinet framing.  

kitchen unit framing forward of the tank space ...

The rear of the tank cabinet will be left open - it's not visible from inside the van and everything will be easily accessible from the outside via the rear doors.  

trial fit of the tanks ...

There's space to the left of the waste tanks and above the wheelarch to stow the drain and filling hoses etc when they're not in use.

Both the fresh & waste water tanks are a translucent white, so we can easily see how full they are by opening the back doors - there's no need to add unnecessary complexity by fitting level sensors etc.

On the opposite side of the van, the basic framing has now been built for the toilet / shower room.   Again, the corner uprights are from right-angle sections made by gluing & screwing two pieces of timber together.   

from the rear ...

from the front ...

There's more bracing required but it's a good start, and this has also enabled me to commence making overhead storage cabinets to the front of the shower room.  I've built two carcasses, an extra deep version nearest the shower room and a longer shallow unit to the front.

trial fit of the overhead cupboards...

The bottom half of the deep version will be the cabin control centre, where all the switches and monitoring equipment will be located.  The top half will be another storage cabinet, matching the depth and style of the three cupboards within the long shallow unit.

I'll shortly need a trip to the timber merchant to buy several sheets of plywood for all the remaining panelling etc.   I'm repurposing all the pieces I originally stripped out, but there's still a significant shortfall.   However, these new sheets will be 2,440 x 1,220 mm (8' x 4') and I'll need to use the van to collect them, so the framing structures must all be self-supporting and properly fixed before I take the van on the road again.  

Therefore the trip to fetch the plywood will also serve as a general road test, since the van hasn't been moved since I started the build.

So that's it for this update, but there's still plenty going on and I'll likely post again next weekend.