Ideas for a natural shower pan?

I'm contemplating a shower in a tiny home.  The owner wants the whole build to be natural (metal allowed).  I'm struggling to find good options for a natural shower pan to collect shower water and keep it from rotting out the naturally insulated floor.  They might be ok with a fiberglass shower base but they're fairly expensive these days.

All I can think of is a metal container of some sort that can be repurposed.  Some options are:

- Galvanized wash tub
       - Pros are it's pretty water proof, would keep a shower curtain contained and could be hauled outside to dump if a drain isn't included.  
       - Con is that it's kinda high to step into and not likely big enough for comfortable shower dancing (24" dia).



- Galvanized square stock tank
      - Pros are that it's water proof, would keep a curtain contained and is shower sized (34" on a side)
      - Cons are that it's $170 so a bit pricier than the alternatives



- Water heater leak catch pan
       - Pros are that it's flat bottomed, water tight, cheap and has a side drain hole
       - Cons are that it's flimsy, may not keep a shower curtain inside it, is only 28" diameter, and has a side drain hole



- Washing machine drain pan
       - Pros: Has a drain, beefy, 32x30 is borderline size, rectangular
       - Cons: Fiberglass, won't keep a shower curtain inside it



- Duct drain pan
       - Pros: didn't know it existed in the world, leak proof, cheap, square
       - Cons: Only 24", need a better threshold, shallow, probably flimsy



- Big piece of galvanized metal and bend it into a pan shape
       - Pros: likely cheap and within my abilities, customizable to fit the shower space, custom threshold height
       - Cons: don't know where to get a piece of galvanized sheet metal that big (48" square?)

Any other ideas or thoughts?  Thanks!

I’d be looking at tadelakt with a drain, but given what you’ve said about prices, it’s hard to imagine anything really working. Steel mesh over a dry well would be too expensive.

There are no cheap new options these days.

The last one I built was from a new base I found at a habitat restore.

I have had a drain trough folded and welded for a shower floor, with the shower floor sloping into it to fit an existing house.
In your case the same could be created.
See the entry below for additional information

From the above image, this becomes the start of the shape, one long edge is extended up to form the lower part of the wall, the ends are also folded up and the other long edge
is folded to slope across the floor pan area with a folded lip to suit the other lips.
Then two strips are welded in the missing parts to form a sloping floor to a drain trough.
A competent sheet metal worker can do this.
The socket dropping down is made to fit standard plumbing bits.

I would look for a local hobby metal worker. A sheet of metal, folded & welded to your specs might be less $$ than you think.

Is cement acceptable?
Before plastic liners, I believe a thick mortar base was used under tile floors.
You could build such a base,tile it and waterproof it with a water glass based sealer.

I think you also could form an all concrete shower pan and waterproof it with a water glass based sealer.

I've been able to create a waterproof finish over a wood countertop with hydraulic cement.
I stapled window screen to the wood, then applied the cement..
This is akin to stucco, flying concrete or ferrocement, but ultimately it is none of these.


I have used this as the counter around my sink for years now, with no signs of decay.

If cement is not ok, what about silicone?
It's rather neutral and can even be found in food safe varieties.
It could be used to seal a tile shower floor, or even a cedar floor.

If there is a waterproof varnish that meets with your natural criteria, cedar dog-eared fence pickets are rather cheap.

It would be an odd choice, but largish  mirrors and glass can be found for pretty cheap or even free.
To avoid drilling the glass, install it with a tiny slope,make curbs around it in another material and put the drain in the downslope curb.

PVC is the cheapest drain material, but it is plastic.
For your drain, stainless steel, or copper are all costly.
Chrome plated brass, preferably 1 1/2" , should be pretty affordable, and from there you can transition to cast iron.

One more thing.
If you can find a stainless steel table for sale, you can invert it and remove the legs.
It will have some kind of rim all the way around, thus forming a wide flat shower pan.
I see them for about 100$ used , if they are dinged up.

Thanks everyone!!  I guess I hadn't thought of the naturality of the drain.  I'll have to look at options but I'm guessing those will end up being pvc.

I like the upside down SS table idea William!  It reminds me that I should go to the surplus/refurbished kitchen supply warehouse and see if they have anything like that.  Or anything else that might work...  We are trying to avoid cement.

I also like the tadelakt idea but I'm guessing I wouldn't be able to get it to actually work.

I don't know any hobby metal benders but I can ask my network.

I am thinking of using the cheap fake metal roofing sheets that they use for wainscoting as the shower walls...

Maybe? 30"×50"

https://www.amazon.com/DiversiTech-6-M3050-Drain-Pan-Metal/dp/B014GZCSZO/ref=mp_s_a_1_13