{EDIT, 3-23-2012}
I should say at the outset, that this is an unusual project. It has been, by far the most unusual from the standpoint that with only one exception, everyone I know, every friend I have, male or female has not supported this project. 'Not supported' is actually too mild a term, 'strongly opposed' would be much closer to the truth. They all vigorously tried to dissuade me from doing this, they offered me a blizzard of alternatives that they thought were superior. Finally, they gave up and decided that I was too ornery to be reasoned with, and not quite deranged enough to have committed to a mental institution.
However, without exception, now that it is actually built and working, they think it's really great and my strongest critic seems to have forgotten his fierce opposition and has decided to build one, "...just like you did."
Ha!
* * *
My house doesn't have much floor space, about 700 sq. ft. and it was built before an indoor toilet was considered a necessity for a working class family in 1892.
When I moved in, a true water closet had been installed on the back porch and then the back porch had been enclosed. Bathing was accomplished in another poorly conceived room which reduced the size and usefulness of the kitchen.
My goal was to convert the water closet into a Scandinavian style toilet/washroom/shower combo that would offer full utility and take up the absolute minimum amount of space, and to make the space from the old bathing room available to an enlarged kitchen.
The design was for the mini-loo to be as small as possible, allowing for minimum code dimensions.
Since I was going to use the mini-loo as a shower, everything had to be completely water proof... no guessing here.
Initially I had the idea of using a modern Japanese style flushing squat toilet, and having it's drain also be the drain for the shower. I hunted for several days on the Internet and only found one supplier in the US, and the unit was 1,600 dollars, mighty expensive. I also did some surveys and discovered that American women in general do not seem to take kindly to the idea of a squat toilet, in spite of the studies of health benefits I suggested that they read. Perhaps another time...
The project has been quite a success, although I made some mistakes along the way, which I will describe.
Top pic shows the floor joists with blocking reinforcing to prevent any flexure of the floor or walls. It also shows the RV toilet I initially thought I would use for the project. This toilet was the right price (free) but flushed down through the floor, which I would later realize would be very difficult to make completely water proof... more later.
Since I had the floor open, I took the opportunity to replace all of the cast iron and lead waste lines with new ABS.
The bottom pic was taken after the floor, 3/4" marine ply + 3/4" pressure treated ply were screwed down to within and inch of their lives, with coated screws. I found considerable help from a Canadian Tile-Setters blog, regarding exactly what is required for a very rigid floor, even how to lap and how to fasten, with engineering studies supporting the methods. Also discussed in considerable detail was blocking requirements... very thorough.
The sink (upside down) and the floor drain are shown placed on the floor for consideration of fit. The sink was very small and fully functional. I would later realize that the floor drain should have gone in the very center of the floor, but at this time I was planning on the W/C waste line also going through the floor.
Top pic shows shower stall (AKA: wet room) blocking going in. The total blocking phase took considerable time. I used screws and metal brackets throughout and was glad I did, because it allowed me (with only rudimentary carpenter skills and a complete newbee to tile work) to easily re-do parts that were not quite right. The vertical boards at the bottom are for the support of the water proofing membrane that would be a key part of the water-tight strategy.
By the time this photo was taken, I realized that the RV toilet would not be a good choice, both from a water-proof standpoint, and also from an aesthetic stand point. Shown in the pic is the filled-in hole for the toilet. I used the plugs from the hole saw, and glued them back in with epoxy glue. Not shown is a a plywood block underneath the floor to support the glued-in plugs.
Bottom pic shows a fly's eye view of the mini-loo, with my #12 shoe for an idea of the size. The finished width (after tile) is 32.5 inches and the finished length is 49.5 inches.
At the bottom of the pic is the in-wall flush assembly and toilet hanger that is made by Geberit.
It certainly upped the cost of the mini-loo, but it works great. The Toto toilet I found to go with it looks like a normal toilet, and actually takes up less room than the RV toilet.
The Toto toilet & Geberit in-wall assembly were both designed from the beginning to be dual flush. As I write this, I have used the mini-loo for about 5 months, and have not had a single mis-flush. My old low-flush toilet required the very worst kind of plunging at least once a week. I like this way much, much, much better.
(to be continued)
-AC_Hacker