Wall Mounted Toilet Installation

wall mounted toilet before and after

Preparation

 

The idea for wall mounted toilets started at the very beginning of planning and preparing for our Complete Bathroom Remodel. We decided that everything would be wall mounted; toilets, cabinets, vanities, faucets.  Reasons for this:

-Saves space. Wall mounted toilets can save anywhere from 8″ – 12″ in front of the bowl compared to traditional  toilets.

-Bowl height can be adjusted at installation. A big plus if you think your old toilet is too short.

-Ease of cleaning. You know that disgusting spot behind the toilet that you can never really reach, so it never really gets clean? Wall mount toilets don’t have that problem.

-Design aesthetic. We just like the way it looks.

 

To start, you need access to framing, waste pipes, and water supply lines. Since I was completely remodeling both bathrooms, I had this in spades.

bathroom remodel plumbing

The original bathroom configuration had two floor mounted toilets back to back on opposite sides of the adjoining wall, with a 3″ cast iron waste pipe for both. I based much of the new design for both bathrooms around keeping the 3″ waste pipes in roughly the same positions.

wall mount toilet sketchup diagram

Wall Mounted Toilets – Framing

 

Each wall mounted toilet tank frame has specific stud spacing requirements. Many also offer tank frames for either 2×4 or 2×6 construction. Since I was building the new wall that would house the tank frames, I elected to frame it using 2×6 lumber for added structural strength and more space for waste and water supply lines. 
remodel framing

Our Geberit Duofix tank frames required stud spacing of 19 3/4″ so I made sure to plan for this when framing the wall. Note that plumbing code requires 15″ of clear space on either side from the center of the toilet. Be sure to take this into account when planning the locations of toilets and anything else in the bathroom. Read more about codes, permits and inspections (here). Wall mounted toilets also require the waste pipe to drop straight down inside the wall, and through the bottom plate. This necessitates either mostly or completely removing a section of bottom plate. Be sure to add nail plates or metal strapping to protect the waste pipe when installing the finished wall. 

waste pipe nail plate
Sister studs and or additional blocking on either side of the tank frame studs is also a good idea, to add some strength and rigidity to the wall.

Flushing

 

It is especially important to mount the tank frame precisely flush with the face of the framing members. After installing the finished wall in the guest bathroom and mounting the toilet bowl, I discovered a gap between the back of the drywall and the face of the tank frame. This resulted in the drywall, rather than the metal frame, taking the weight of the bowl. I had to cut out a section of drywall and replace it with plywood to provide solid bridging between the bottom of the bowl and the metal tank frame. 
flush framing

One more note about this phase of wall mounted toilet installation I wish I’d known sooner. The mounting bolts provided with our tank frame were a very loose fit in the threads of the frame. I ended up, again after installing the finished wall, securing the bolts to the frame with washers and nuts. There was no mention of this in the installation manual or any manufacturer videos I found. This would have saved cutting out more drywall.

wall mount toilet hardware

Wall Mounted Toilets – Plumbing

 

The most difficult aspect of wall mounted toilet installation is accommodating 3″ waste pipes. Joist depth and spacing, underfloor access, and other framing details can be major constraints if you need to reroute these large pipes.  Because of this, I elected to keep the 3″ cast iron double fixture fitting and drain pipe where they were, and design most of the rest of the space around this fixed element. Water supply was much easier. I used PEX for all of the new supply lines, and a 1/2″ NPT elbow with PEX adaptor to make the connection to the tank. Since this was a permitted project and I was having my work inspected, I followed the generally accepted practice of omitting the toilet for rough in inspection. With a standard floor toilet, the flange is normally installed and capped for rough in. In my case, I stubbed out the waste lines to the proper height, then capped with Fernco caps so I could fill the DWV system for testing. The Inspector was not very familiar with wall mount toilets, but seemed happy with my work and gave me a pass for the plumbing rough in.
wall mounted toilet plumbing
wall mount toilet plumbing
wall mount toilet tank frames
wall mount toilet tank frames

Wall Mounted Toilets – Bowl

 

When planning a wall mounted toilet installation, be sure to select a compatible bowl/tank combination. Not all bowl makes and models will work with all tank makes and models, and you could end up with limited choices for one or the other. We opted for Duravit Rimless bowls and are quite pleased with them so far. After installing the finished wall surface, I mounted the bowl to the tank frame. As I noted earlier, it’s especially important to have zero clearance between rear surface of the finished wall and the front face of the tank frame. It may be necessary to use a thin strip of hardwood, plywood, or something similar to eliminate any gap. Following the installation instructions, I measured and cut the water inlet and waste outlet pipes.  
wall mounted toilet hardware

Wall Mounted Toilets – Bowl

 

When planning a wall mounted toilet installation, be sure to select a compatible bowl/tank combination. Not all bowl makes and models will work with all tank makes and models, and you could end up with limited choices for one or the other. We opted for Duravit Rimless bowls and are quite pleased with them so far. After installing the finished wall surface, I mounted the bowl to the tank frame. As I noted earlier, it’s especially important to have zero clearance between rear surface of the finished wall and the front face of the tank frame. It may be necessary to use a thin strip of hardwood, plywood, or something similar to eliminate any gap. Following the installation instructions, I measured and cut the water inlet and waste outlet pipes.  
wall mounted toilet
wall mount toilet

The only thing still missing is the flush actuator plate, which I plan to custom fabricate in the shop to match the rest of the finish trim in the bathrooms. Look for an update when that’s complete.

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