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Discussion Starter · #1 · (Edited)
We are getting our 2nd story bathroom updated. When the old floor tile was taken up we found a leak from the toilet which damaged the plywood and called for part of ceiling downstairs to have to be cut out due to mold/rot. Supposedly the toilet was not set right on seal which caused the slow leak.
My concern is, the foor guy put the new plywood around the toilet flange with the seam of two pieces of plywood right up the centerline of the flange (where the toilet will sit) instead of using one piece of plywood with a hole cut out for the flange.That area with the seam doesn’t feel strong. If i step on both sides of it it rocks. Cement board will go on top and then tile but should the plywood have been installed differently? There is not much support around the flange underneath the plywood just to note. There is just a piece of wood behind the flange under the floor.
Also, should the flange be above the plywood more than what it is to make room for cement board and tile?
 

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Naildriver
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The plywood seam needs to be supported for it's entire run, whether it is perlins across the joists, or an additional joist with a perlin across the end where the flange is locate and joist hanger on the other end. If it is flexing, now, CBU won't help as it is there for a flat surface, NOT support. The flange being above the plywood is correct. Your CBU will go around it and will allow for the tile to be slightly even or above the flange, which is fine.
 

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Discussion Starter · #6 ·
The plywood seam needs to be supported for it's entire run, whether it is perlins across the joists, or an additional joist with a perlin across the end where the flange is locate and joist hanger on the other end. If it is flexing, now, CBU won't help as it is there for a flat surface, NOT support. The flange being above the plywood is correct. Your CBU will go around it and will allow for the tile to be slightly even or above the flange, which is fine.
Thank you for the response
The plywood seam needs to be supported for it's entire run, whether it is perlins across the joists, or an additional joist with a perlin across the end where the flange is locate and joist hanger on the other end. If it is flexing, now, CBU won't help as it is there for a flat surface, NOT support. The flange being above the plywood is correct. Your CBU will go around it and will allow for the tile to be slightly even or above the flange, which is fine.
Thank you for the response. So i should have the floor guy take up the plywood and add what is needed? This would be his second time doing the subfloor. The first time I brought OSB and let him have at then read that plywood probably is best for bathroom so he kindly took up what he did and put the plywood down. Did you see the pictures I posted. Does it look like it would complicated for him to create a more stable/secure floor in that area
 

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Naildriver
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From what I am seeing you only have 1/2" plywood as a subfloor, which is not adequate enough for tile. You need to add a 3/4" layer (advantech) to provide good support. He can lay the new additional subflooring directly on your plywood and you won't know the difference.
 

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retired framer
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When you patch plywood you do not have tongue anf groove to support the edges between the joists you need plywood or 2x4 blocks under the join with glue and screws to make the 2 sheets one.

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Discussion Starter · #9 ·
From what I am seeing you only have 1/2" plywood as a subfloor, which is not adequate enough for tile. You need to add a 3/4" layer (advantech) to provide good support. He can lay the new additional subflooring directly on your plywood and you won't know the difference.
We actually used 3/4 inch plywood so would 1/4” of advantech go on top of entire floor, In addition to the 1/2” cement board?
 

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Naildriver
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You'll need a total of 1 1/4" of subflooring, so 1/4" won't do. 1/2" on top of the existing 3/4" will make it stiff enough. You only use 1/4" CBU on the floor and it doesn't add any strength at all. It is only a flat surface for your tile.
 

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Discussion Starter · #13 ·
We actually used 3/4 inch plywood so would 1/4” of advantech go on top of entire floor, In addition to the 1/2” cement board?
I actually like that idea of adding another layer with the advantech. Will the space between the two boards (plywood & advantech) pose any issues? I can’t imagine it would. My floor guy is going to be so over me!! This job has me so paranoid. We had no issues with the flooring prior to the demo. Only difference pre & post project will be the placement of cut with the plywood but I was reassured everything will be fine.
 

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Naildriver
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Will the space between the two boards (plywood & advantech) pose any issues?
There should be no space. HOWEVER, there should be no glue, either. And your fasteners should intentionally miss the joists, so as to allow for slight movement between the two layers. It is minimal, but it is there.

Oh, you can bet he will spit in your ice tea :) You are adding a lot of work that wasn't covered in the beginning, so be ready to pay for it.
 
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Just my two cents.....when it comes to building and construction, the best advice to follow here is Nealtw's.
HIs experience is worth noting.
I spend some time on this forum and he always has the most practical advice on building matters.
 
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Discussion Starter · #18 ·
Tub goes in first on the sub floor. After extra plywood if you do that. Standard tub.
Thank you.
For the walls around the tub/shower. Does sheetrock/drywall go up first (nailed to studs) and then cement board on top of sheetrock/drywall? Or is it normal to just put up cement board only?
 

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retired framer
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Thank you.
For the walls around the tub/shower. Does sheetrock/drywall go up first (nailed to studs) and then cement board on top of sheetrock/drywall? Or is it normal to just put up cement board only?
No, not the way I would do it, tub against the studs, CMU above the tub flange and I put a row of tile down the side of the tub to the floor and behind that tile is where you change from CMU to drywall

Put blocking for the CMU too.
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Discussion Starter · #20 ·
Tub goes in first on the sub floor. After extra plywood if you do that. Standard tub.
For the install i brought American Standard Elevate acrylic tub. We like that it is deep however the plumber is trying to persuade me to get a porcelin enameled steel tub instead like the Mansfield Pro Fit Cast. Any thoughts? We had a fiberglass tub for at least 13yrs with no issues prior to this remodel
 
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