The bathroom is plumbed inside the stud walls. The old bathroom had a prefabricated fiberglass enclosure. The flange was behind it. It wasn't attached to the wall, or anything other than its plumbing. I have to build a wall behind the toilet (and protect all the plumbing back there, too), and want to attach the flange to it. I'm thinking of a 1x12 for sturdiness. But the flange fits inside the back of the toilet, about a half-inch recessed. Is there some part I'm missing?

? rear outlet or wall mounted ?


for a rear outlet which 'sits' on the floor: [www.bing.com]



for a wall mounted which requires a 'chair carrier': [www.bing.com]

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

yeah, you are missing the bowl wax. the toilet installs just like a regular floor type toilet. some of your type bowls have a place for screws to go thru to the floor to keep the bowl from moving. otherwise use some clear silicone caulk on the bottom to literly glue the bowl to the floor.
a couple of 2x4'sturned sideways behind the flange will give plenty of strength to secure the flange.

It sits on the floor.

I should have been specific and written that I want to attach the flange to something. I don't see how 2×4s will help. I have a bunch of plumbing in that area that I want to protect and hide, so plan to build a 4' high wall behind the toilet. There isn't enough space under the toilet's drain for an upright 2×4 so the one on the floor will lie flat. But the wall will have a gap of about ½" behind the flange because of the recess of the toilet. I could just screw the flange to the wall but it would be more stable with something in between. I wondered what plumbers do.

I've needed to move my toilet too many times to glue it down. The holes in the bottom aren't over a joist, wouldn't hold well in the plywood, and would leak. I've lived here 20 years without it being a problem

If you moved the toilet that many times you do have a problem.

the holes in the bottom of the toilet bowl are for securing the toilet to the floor.plywood is plenty strong.
all toilet bowls have a space between the bowl and the flange.
toilet bowls have a "horn" that sticks out which the bowl wax sets around.
the wax itself is thicker than 1/2 inch so it gets compressed as you tighten the flange bolts.
make sure the wax is nice and warm (not too warm) so it will compress nicely.
[www.jimmyjoesplumbing.com]

@OP,

the pic in packy's link is of an IMPROPERLY installed and thereby LEAKING toilet

a proper installation:



BOTH the toilet and the FLANGE rest ON TOP OF the finished floor

the wax serves merely as a gas seal - the 'horn' of the bowl is LOWER than the top of the flange

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

The flange has holes for attaching to the floor (or, in my case, wall): that's what I'm talking about, not connecting the toilet to the flange. I want something to hold the flange back when I pull the toilet out. I hate wax, use a Fernco FTS-3.

When I renovated the bathroom I found the wood underneath the toilet delaminated and punky - and there weren't even screws in the floor to hold it down. A slow leak, could have been decades, had drilled a small hole, dime-size, through ¾" of plywood, damaged the drywall in the ceiling below. I replaced it all. I won't put a hole in the floor.

you install the wall flange the same way you install a floor flange

AFTER the finished surface

you will need plywood for the wall AND a folding rule just like setting a cabinet

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

the screws thru the holes into the floor are important.
if you want, set the bowl dry in place, mark the holes, remove the bowl, drill some holes for stainless screws, shop vac the holes clean, put the bowl wax (or whatever you want), set the bowl, tighten the toilet bolts, smush some caulking into the holes in the floor and then install the floor screws.