prepping subfloor for tiling
 

I'm trying to replace the ceramic tile in our bathroom. The problem is
that there is a gap around the toilet drain pipe. The subfloor is not
quite flush w/ the drain pipe, and there is an even larger 4" x 2" gap
in the concrete backerboard that the tile rest on (the previous
handyman just filled in the gap w/ putty).

My question is: can can i best fill this gap? my concern is that even
if i replace a portion of the backerboard, it won't be supported and
the tile or the grout between them will crack. The back corner of the
toilet rests in this gap, so there will be pressure on it. Right now I
have a shim screwed between the floorboards to support the toilet, but
i'd like to have something more durable than a shim. Any ideas?

davidmc,

You need to add some information please.

davidmc wrote:
I'm trying to replace the ceramic tile in our bathroom. The problem is
that there is a gap around the toilet drain pipe. The subfloor is not
quite flush w/ the drain pipe, and there is an even larger 4" x 2" gap
in the concrete backerboard that the tile rest on (the previous
handyman just filled in the gap w/ putty).

Is there a toilet flange on the drain pipe? Is it resting on or
attached to anything other than the drain pipe? Is it cast iron or plastic?


My question is: can can i best fill this gap? my concern is that even
if i replace a portion of the backerboard, it won't be supported and
the tile or the grout between them will crack. The back corner of the
toilet rests in this gap, so there will be pressure on it. Right now I
have a shim screwed between the floorboards to support the toilet, but
i'd like to have something more durable than a shim. Any ideas?

I'm still not quite clear on your predicament as to where this gap is
and if it is part of the gap you mentioned around the drain pipe.
However you may need to go below the backerboard and add some plywood or
even below the floor and add a piece(s) of 2X for backing as well around
the drain pipe and flange, or at other places where there is no
subflooring.

Put some thin set morter under the backerboard before replacing the bad
section. the thin set will fill any voids and provide solid support. Fix
any rotten wood in the subfloor before mudding it up. Oil based primer can
seal minor moisture problems that have not gone to rot. You might be able
to just patch with thinset but I doubt it is that easy, would need to see it
to say.


"davidmc" wrote in message
ups.com...
I'm trying to replace the ceramic tile in our bathroom. The problem is
that there is a gap around the toilet drain pipe. The subfloor is not
quite flush w/ the drain pipe, and there is an even larger 4" x 2" gap
in the concrete backerboard that the tile rest on (the previous
handyman just filled in the gap w/ putty).

My question is: can can i best fill this gap? my concern is that even
if i replace a portion of the backerboard, it won't be supported and
the tile or the grout between them will crack. The back corner of the
toilet rests in this gap, so there will be pressure on it. Right now I
have a shim screwed between the floorboards to support the toilet, but
i'd like to have something more durable than a shim. Any ideas?

Yes, there's a metal flange around the drain pipe. 3/4s of the flange
is resting on the ceramic tile, but the rest is unsupported w/ no tile
or subfloor underneath it. To clarify, the gap is around the drainpipe
and the flange. It would be difficult to replace sections of the
subfloor b/c it consists of 2 layers of wide, long planks that extend
into the next room. I was thinking about using epoxy or something to
patch the subfloor, and then replacing a section of the cement board.

davidmc wrote:
Yes, there's a metal flange around the drain pipe. 3/4s of the flange
is resting on the ceramic tile, but the rest is unsupported w/ no tile
or subfloor underneath it. To clarify, the gap is around the
drainpipe and the flange.

So whoever put in the subfloor (what is the subfloor on?) didn't extent
it quite far enough (1/4 the width of the flange).

I don't see that as any big deal, just take up the flange and old tile,
re-tile as far as you can.

After all, the flange/tile "as is" has been supporting the john and
rider, so will putting stuff back in the same way...no need or reason to
make a nightmare job trying to get new subfloor/tile up chock-a-block to
the drain pipe.


--
dadiOH
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