My small bathroom job just got bigger. I want to replace the tile
and toilet in the kids bathroom. It's about a 3' by 5' room with a
toilet and tub/shower. I pulled up the tile and saw that 2nd layer
of plywood was black and moldy behind the toilet, in the corner by the
bathtub. So, I decided to pull that up too, and I plan to put down
hardi board instead.

Well, it appears that the water also got down to the main floorboards
(subfloor?) in that corner. I went down to the basement and checked
from above, and I'm happy to report it doesn't show any signs of
rotting from the bottom. But, the top shows water damage; discolored
wood and some of the layers of plywood has rotted away. I have a
fan running in the room now to dry out the wood. When I step and
press the floor in the worst spot, it does not sag.

I took some pics if that helps:
floor: http://mysite.verizon.net/paulaner/bathroom.jpg
basement: http://mysite.verizon.net/paulaner/basement.jpg

Here's my dilemma. The house is a rancher, and the walls are not
aligned with the beams below. The beams are 2x4 with vertical
diagonal spacers supporting the whole house on the cement foundation
perimeter. So, in order to tear up this rotten piece of wood and
replace it, I'll have to move the bathtub, and the wall behind the
toilet if I want to cut out a section that can be nailed back down to
the beams below. This is looking to be a much bigger job that I want
to get into.

I believe the wetness is a combination of things: 1. my boys had very
bad toilet 'aim' when they were younger. 2. they didn't always close
the shower curtain correctly. 3. the house is ~ 20 years old and
we've been here 7, so who knows what else occurred before. The boys
are older now, and are much more responsible for that area.

So, finally my question. Do I need to move the tub, tear up the
walls, cut away the flooring and replace it at the beams? Or, can I
dry out the floor, clean up the wood with bleach & natures miracle,
then lay some new hardi board over the whole thing? I plan to tile
and seal the floor when I am done. If I go the easy route, is there a
wood treatment I can put down to level the wood in that rough spot?

Ugh. Thanks in advance.

Paulaner wrote:
snip
Well, it appears that the water also got down to the main floorboards
(subfloor?) in that corner. I went down to the basement and checked
from above, and I'm happy to report it doesn't show any signs of
rotting from the bottom. But, the top shows water damage; discolored
wood and some of the layers of plywood has rotted away. I have a
fan running in the room now to dry out the wood. When I step and
press the floor in the worst spot, it does not sag.
snip
So, finally my question. Do I need to move the tub, tear up the
walls, cut away the flooring and replace it at the beams?

No, you said the plywood underneath is solid so leave it in place.
Even if you did decide to cut it out you could put blocking between the
floor joists to support the edges of the new smaller patch. You are
right to go with the backerboard or cement board. Plus, nobody could
walk back there once the toilet is in place except an elf and I hear
they don't weigh much.

In article ,
says...

My small bathroom job just got bigger. I want to replace the tile
and toilet in the kids bathroom. It's about a 3' by 5' room with a
toilet and tub/shower. I pulled up the tile and saw that 2nd layer
of plywood was black and moldy behind the toilet, in the corner by the
bathtub. So, I decided to pull that up too, and I plan to put down
hardi board instead.

Well, it appears that the water also got down to the main floorboards
(subfloor?) in that corner. I went down to the basement and checked
from above, and I'm happy to report it doesn't show any signs of
rotting from the bottom. But, the top shows water damage; discolored
wood and some of the layers of plywood has rotted away. I have a
fan running in the room now to dry out the wood. When I step and
press the floor in the worst spot, it does not sag.

I took some pics if that helps:
floor: http://mysite.verizon.net/paulaner/bathroom.jpg
basement: http://mysite.verizon.net/paulaner/basement.jpg

Here's my dilemma. The house is a rancher, and the walls are not
aligned with the beams below. The beams are 2x4 with vertical
diagonal spacers supporting the whole house on the cement foundation
perimeter. So, in order to tear up this rotten piece of wood and
replace it, I'll have to move the bathtub, and the wall behind the
toilet if I want to cut out a section that can be nailed back down to
the beams below. This is looking to be a much bigger job that I want
to get into.

I had a similar situation, except it was under a sink in a 3x5 1/2
bath. A pipe sprang a pin hole and leaked just enough water to
ruin the subfloor but not be detected until I pulled up the vinyl
floor. Not even enough water to stain the sheetrock in the kitchen
below. Unfortunately, both layers of subfloor had to come out.

I believe the wetness is a combination of things: 1. my boys had very
bad toilet 'aim' when they were younger. 2. they didn't always close
the shower curtain correctly. 3. the house is ~ 20 years old and
we've been here 7, so who knows what else occurred before. The boys
are older now, and are much more responsible for that area.

So, finally my question. Do I need to move the tub, tear up the
walls, cut away the flooring and replace it at the beams? Or, can I
dry out the floor, clean up the wood with bleach & natures miracle,
then lay some new hardi board over the whole thing? I plan to tile
and seal the floor when I am done. If I go the easy route, is there a
wood treatment I can put down to level the wood in that rough spot?

DIYer_Alert;

I agree with RayV, if the subfloor is solid, leave it. You *could*
use some leveling compound on the subfloor, but I think it's a
waste of time since you're going to use thinset for the hardi-
backer anyway. If it's really rough, you might want to level it
with thinset before installing the Hardibacker so the thinset for
the backer is easier to get troweled on right. I'd screw down the
subfloor to the joists before putting down the hardi-backer just to
make sure nothing is going to move.

Yes, some bleach to kill any mold and perhaps a week with a fan
running to make sure everything is perfectly dry is a good idea.

/DIYer_Alert;

--
Keith