I seek advice for a project of mine.
I intend to have a wall-mounted toilet in my new bathroom. I have NOT built the wall as yet- that’s where I seek advice.
The house is conventional stick-frame, built over a crawl space. I have two questions:
1) How “fat” need the wall be, to allow for connection between the toilet as well as to allow room for the drain pipe / vent stack to pass (pipes will be vertical, between studs)?; and,
2) Hanging a toilet off the wall applies quite a ‘moment’ to the wall. What would you do to make sure the wall was stiff enough?
Replies
if you have the room, put up a 2x6 wall on the your plumbing will be.
In commercial settings (wall mounted fixtures) I ususally have a sheet of plywood put on after rough in that covers the entire back wall and blocking on sides where ada bars need to be. If you dont want the extra 5/8'' then i would say knotching the 2x and putting in a 2x8/10 block across 3-4 studs.
wall mtd toilet
You need to get and read the mfrs. installation/mounting instructions for the unit you plan to use.
The commercial wall-mounted toilets I've studied from behind mostly appeared to have a cast-iron frame that was bolted to the floor. My vague recollection is that it projected 16-18 inches rearward at the floor, and all the plumbing was well within that distance.
(Access from behind to service the connection appears to be highly desireable, if not absolutely necessary.)
Closet Carrier
You need to buy a closet carrier. Most likely this will come from a different manufacturer than the toilet. I think double 2x4 studs should be structurally adequate but you may need greater clearance for the plumbing.
http://www.zurn.com/Pages/ProductsList.aspx?NodeKey=322315
Research the manufacturer's info...
I have used Toto's version and found the spec information on their website in about 5 minutes - they have a frame that's installed in as narrow a wall as 2x4's. The frame is about 2' wide, 4' tall, 3.5" thick - it includes the tank and flush mechanism and the mounting bracket for the toilet surounded by a steel fram. It's basically installed like a door - you frame out a rough opening with king and jack studs each side and a header above..Toto's frame is then installed resting on the sill plates and is supported from tipping over by laggiing into the studs each side. See PDF attached.
I have also worked on commercial projects that have big cast iron 'carriages' for supporting wall hung units..theses require wall thicknesses of 1' or so.
You really just need to do your research and pick a product that works for you..
Nice Info, May Be Useful
I have been looking at 'flushometer' toilets, and not the concealed tank type that you referenced. Thank you for the link; it's more informative than most.
The sheet you reference is a little bit misleading. I am told that I MUST have a 4" sewer connection; once you allow for pipe hubs, you're looking at more than 2x4 framing.
Here's the rub ... it's not enough that the wall simply hold the toilet 'up.' Carriers get attached to the wall. It doesn't take much flexing for wall tile to pop free. Doubled 2x4's (as one suggested) are no stiffer than a single 2x4; I suspect that the king stud arrangement shown in the literature is just as flexible.
Naturally, a 2x8 is a lot stiffer than a 2x4. I'm willing to frame this wall with 2x8's. I'm even willing to use 2x10's. What can I do to get the most stiffness out of this wall?
Apart from tile concerns, my general observations inspire me to be very conservative when it comes to toilet mounting. Nearly every failed bathroom I have seen had the trouble begin at the toilet, where a minor 'wiggle' let water in, leading to rot, etc. Before you know it, you're ripping up the floor and replacing it.
Likewise, every failed door I've seen started with a hinge that wasn't properly anchored to the wall. The same concern (moment) applies to toilets, but greatly magnified, as people tend to weigh more than doors.
In a situation like this, it might be worth getting some LVL or LSL studs. Or even rip a few studs out of pieces of LVL.
We have a few odd/short pieces of LVL laying around most all the time. Usually sell them pretty cheap.
BTW - LVL scraps can make real nice blocking. Very dense wood that hold screws or lag bolts well.
If you don't know- DON'T GUESS!
Wall mounted toilets are actually mounted to a 'carrier,' an iron frame. Some companies make carriers; others make the toilets. None appear to make both.
Instructions provided at multiple toilet manufacturer's sites provide absolutely no information regarding the wall that supports it all. Calls to two toilet manufacturers were not productive.
Ditto for the carrier makers. While I can get dimensions for the carriers, there is no information as to wall construction. Facing the wall with plywood might interfere with mounting the toilet, if I understand the cut sheets correctly.
The carrier dimensions suggest that it might be possible to fit all the plumbing into a wall framed with 2x6's. Having opened such a wall, this requires removing the entire bottom plate to make room for the 4" sewer line.
The issue of wall strength / stiffnessis not addressed in anything I have found. Everyone seems to assume a block wall.
This is one instance where 'read the instructions' seems to not apply.
You might want to try Terry Love Plumbing
You could try http://terrylove.com/forums/index.php with your questions...he's got a great forum for plumbing questions.
Most carriers for commercial toilet installations are floor mounted and don't depend on the walls to carry any of the load. However, Zurn makes one for residential wall hung toilets that's fastened to the wall by bolting thru double studs each side. Zurn model Z1280. The minimum stud size noted are double 2x6's.
Regarding your question about the 'moment' load on the studs - the load the toilet imposes is relatively close to the end of the studs which really minimizes the stud's deflection (much like a floor has very little deflection near the bearing points and much more near mid-span). Also, having double studs, no matter the size, is always stiffer than a single stud. The load being applied is distributed over twice as many identical structural members. Increasing the width of studs is always a great way to resist more lateral loads...without looking up capacities on a chart, I suspect an 8' 2x6 stud can resist more than twice the load of a 2x4, even though it's only 2" wider - especially with deflection as the criteria.
If Zurn specifies using two 2x6 continuous studs each side and you want to use double 2x8's....sounds good. They're a great company.
Also...just a general observation..
You never stated why you wanted to install wall hung toilets. I would never recommend one to a client unless they had very specific desires to use one (ie...a 'minimal' design where only the bowl is visible - like the Toto designs where the tank and other plumbing is concealed in the wall). We had a client that wanted to use them in an upscale house that had 8 toilets - his reasoning was to make it easier on the cleaning lady!! I suggested we offer the lady the choice: easier cleaning around the bathroom floors ...or... the $10K difference between wall hanging and floor mounted toilets. Let her make the choice.
IMHO....Toilets do much better sitting on the floor where they can be adequately supported ...your concerns about the whole wall hanging system is a harbinger of things to come. In addition, there are very few wall hung design options to pick from, which may lead to problems in the future should you need to replace the unit..
Excellent Help- Thanks!
I had missed the Zurn carrier. That's some good information there.
I have a bias towards what I see used in demanding applications. I mean ... all those commercial establishments, institutional buildings, and industrial plants can't be fools. I've seen far too many issues with 'residential' toilets.
A lot of those issues seem to disappear when you replace the tank with a flushometer (those 'wiggle the handle' things you see in public restrooms. So, I plan to have such a toilet in my remodel.
Why wall mounted? Well, the short version is that I intend for the entire bathroom floor to be one big 'shower pan.' That is, water hitting the floor anywhere will be directed to a drain, and the entire floor will be finished - including those spaces "under" appliances. Naturally, the fewer penetrations, the easier it will be to have a durable seal and proper slope.
This plan of mine addresses the failures I have seen, failures that led to bathroom floors rotting away. These leaks almost always appear either under the toilet, or along the edge of the tub (or shower) basin. Instead, water will be directed to two drainage troughs, and the "pan" will extend about 8" up the walls all around. I plan to have the floor be a single, solid piece (such as terrazzo). No seams, few holes = few leaks.
Mounting the toilet on the wall eliminates one of the main sources of such leaks.
I figure that any "design" that can stand up to hardened criminals will perform well enough in my household. My bathroom plan shares these, and other details, with the remodel I participated in at a State Prison (as the electrical contractor).
With my water supply line already over 50 years old, it's due for replacement. I might as well replace it with the larger 1" line a flushometer requires.
Folks are always saying "but it costs more." Funny how they never say that when they're discussing dream cars! In truth, a commercial wall-mount toilet AND flushometer AND carrier cost less than the fancier homeowner models. I'd rather pay to have something 'done right' than 'done over.'
An Idea With Merit
Engineered wood is sure to be both stiffer and more water-resistant than simple lumber. With the addition of metal connections to the top and bottom plates, and I expect the wall will be as stiff as possible.
Eliminate source of leak?
You're assuming the wall mounted toilets never leak...the only toilet to leak (that I know of) in my 40 years of practice was a wall mounted tank type toilet in an attic master bathroom about 20 years ago...we didn't have the floor joist space to install a standard toilet and opted for a wall mounted version. Leak started about 3 years after install - if I recall, it had a rubber gasket at the wall connection and there was just enough movement in that connection to leak when there wasn't a persons wieght on the bowl.... Client was understandably upset - refused to reinstall the same toilet after a couple of failed attempts....had tile walls, etc...ended up raising floor at toilet to give enought room for bend in waste line below the floor. Not a very elegant solution, but never leaked again.
Any toilet can leak if improperly installed. And the key to a leak-free installation is a rigid connection with no movement.
Illogical
I do not assume a wall-mounted toilet will not leak. A toilet can also break or over-fill.
No, I wish to lessen the chance that such a leak would cause damage. Let's look at that damage ....
All too often, we see water find its' way under the toilet itself, where it sits and fosters rot - the sort of rot that ultimately leads to the floor itself failing. Not the 'finish' of the floor, but the structure itself. You know the feeling, where the area around the touilet starts feeling spongey as you stand on it. Let it continue, and you might even put your foot right through what used to be a solid floor.
A similar mechanism works along the outside edge of the tub, or the shower pan.
My solution is to make the entire bathroom floor a single waterproof pan, directing all water to two drainage troughs.
This pan can itself leak at any penetration. By eliminating the openings the toilet would put in the floor, I eliminate possible leaks. Any leaks at the wall face would drain either into the pan- or through the wall cavity into the crawl space. There's limited opportunity for the water to become trapped.
Did I say TWO drains? Yes, I did. This is both to reduce slope and to provide redundancy ... should one drain become plugged, the second will take away the bulk of the water. Clean-up is as simple as using a squeegee - and without there being any 'pockets' around fixtures to trap any water.
That's also why I plan on having a floor that is a single piece ... if not terazzo, then some manner of cement product (like the stuff used on aircraft carrier decks). No tile, with all those grout seams to fail. I'd rather have a single sheet of linoleum than tile for this bathroom.
It's also why I wish for the 'floor' to continue UP the wall several inches. In short, I plan to have the same floor that has proven itself in countless kitchens and hospitals.
The wall-hung toilet is only one part of this plan.
Patience is rewarded
As luck would have it, today I was on a job where such toilets will be used.
I was interested to see that the walls will be simple light steel studs, similar in size to 2x4's. While there is a 12-1/2" space between the bathroom wall and the outside wall, there is NO additional support added to the wall.
In other words, the loads will be carried entirely by the carrier ... which, in turn, relied upon two massive bolts set into the concrete slab.
The sewer pipe is centered in the space between walls, and appears to be perfectly placed for the sewer connections on these particular carriers.
I will watch this job closely, and see what I can learn. Perhaps it's the floor I need to worry about- not the walls!
The bracket I bought had holes in the sides and I used them too along with red heads into the slab.
wade or zurn
All commercial closets carriers I have worked with must be anchored to a concrete slab, however, there are several carriers for residential use that anchor to beefed up wooden framing. Please note that commercial flushometers are reliant on large capacity piping, and consistent water pressure; flushometers also do not like water with condition or chemistry issues - water with suspended particles, or mineral hardness will not work well with a flushometer..........
A floor mounted, gravity flush toilet, will sit leak proof and odor free for decades or longer - if it is installed on a properly prepared floor and flange - look for my article about this in an upcoming issue of FHB magazine.
At first, you may think that choosing a toilet is an easy task. It will all change once you find all the options. You’ll likely spend some time thinking over wall mounted vs floor mounted toilets. A wall-mounted toilet is mounted on the wall and doesn’t touch the floor. It’s elevated for a few centimeters and the tank is hidden in the wall so it can save you some space in your bathroom.