I am trying a DIY repair job of the area in front of my stand up
shower. I cut the floor open, removed the wet insulation, etc. The
problem I have is the plywood (or pressboard in this case) goes under
the wall to the left (in photo) and up under the shower for a couple of
inches. I need to remove that on both sides and install the new
plywood. My problem is properly removing the plywood and installing the
new. It is underneath the 2X4s, so unless I cut a hole in my ceiling
from below, I won't be able to re-attach if I'm even thinking
correctly. There was also a cement like corner at the corner of my
shower that was connected to a small piece of plywood (it fell down on
it's own) Any ideas?? I've been googling for 2 days, lol.
Question that popped up on reading this: suppose you were to gut this
(or a similar) water-damaged bathroom to the floor joists and wall
studs where water damage was fairly heavy in one corner and along a
wall. Aren't some wall studs and the plate they are nailed to going to
be sitting upon soaked-through underlayment and subfloor? Do you dig
that out and attempt to wedge in new materials?
The rot ends right under the 2X4 to the left and 2-3 inches under the
front of the shower. This occured due to water pooling because of tile
broken and splash guard lifted up on one side. There is no plywood
under the shower. It sits on a wood frame that is undamaged. I
removed and am replacing the insulation and have treated/treating only
slightly damaged material (wet spot on a solid 2X4). My biggest
problem is the fact that the plywood goes under the wall and comes out
in a hallway. The floor is fine in the hallway (to the left of the
hole), but the plywood needs replacing under the wall. There doesn't
appear to be any damage to any of the beams underneath the floor
besides the one wet spot that is recent. (A couple of days old and I
have stablized and will also epoxy). I definitely need to go get a
reciprocating (sp?) saw.
(Will reply to others as soon as I have had a nap, been working on this
The house is only 8 years old. They used pressboard instead of regular
plywood with the thin sandwiched stuff on top...then linoleum.
I want to put in better wood in front of the shower, but I'm concerned
about the wall to the left because that pressboard that I cut a hole in
extends under the wall (2X4 where sheetrock goes) to the hallway. No
damage in the hallway. Damage only extends to beneath that 2X4. Full
overhaul of bathroom is a no-no, due to wife starting a new business
and sucking my paycheck to next to nothing. I plan on putting roofing
tarp on top of the new plywood and water protecting the area before I
put the new sandwiched board on top. I am primarily interested in just
repairing the area for now. Right behind the shower is another
bathroom, so no we don't smell too bad...lol.
Sorry if this doesn't make sense, as I'm currently sleep deprived... ;-)
The shower is sitting on a wood frame and is undamaged. The house is
only 8 years old and the shower base was untouched. The vast majority
of the damage was in the left side of the area I cut out. I cut a
bigger hole because I plan to replace the plywood in front of the
shower (extends a few inched under the front lip of the shower) with
something a bit stronger and seal it real well to keep from having to
do it again. (Of course I'm going to seal the tile in the corner when
I prepare it REAL well and keep a better eye on these kinds of things
from now on) The underside of the fiberglass base is also reinforced
with concrete and metal. It is okay except for the one corner. I can
jump up and down in the shower and it's solid as can be.
Not sure if a DIYer should attempt it, but I would rip everything out of the
bathroom and replace the entire floor. The wood under the shower base is
probably rotted out to the point it may collapse on you sometime in the near
Pain in the butt and could be a costly job, but you really should do it
right so you won't have problems again in the future....
If the floor was a single layer under the vinyl or tile whatever, what you
probably have is one of those 'all in one' subfloor systems that were
popular very briefly 20-some years ago. Not plywood, not chipboard, but
related to both. Stuff was supposed to be a labor saver during construction,
but as you have found out, damn hard to repair. When I was house shopping, I
passed up an otherwise interesting house to avoid the stuff.
No great ideas to offer. Short of a major remodel to repair it properly,
fake it as best you can. Cut the stuff as close to wall as you can, pick out
as much of the rot as possible from under the plate, stabilize with epoxy or
whatever, and shove some blocks in there if possible. To hold the new
plywood subfloor, screw 2x cleats to the joists wherever possible, and work
some joist-to-joist blocks in under the shower. It won't be easy, and
whoever fixes it right in twenty years will laugh, but it will work. Those
metal nailer plates they sell for decks, and a screw shooter, can be handy
in spots too tight to swing a hammer. Unless ceiling below has a texture
finish or something, probably be less labor to open it up for access. That
drywall did get wet, so is damaged anyway. Not sure what you mean about the
cement-like corner ; didn't see that in the pictures.
Personally, I'd go ahead and finish gutting bathroom, and get it over with.
Looks like you have half the demo done already. If your budget won't cover a
new tile job, some of the old-work shower kits (3 walls and a pan that snap
together) actually look okay. Gut it, put in new plywood subfloor, cement
board if you will be putting ceramic floor, cement board with proper
flashing around shower walls, greenboard on other walls, and build it back
out with a fresh interior. It'll cost more, but you'll never have to mess
with it again. I take it there is another bathroom in the house?
I asked about damage to the floor going under a wall because, like you,
that is a problem I'll have to face soon in a second bathroom. Mine is
a long-standing toilet leak several owners back.
FWIW, I'm considering the Clear Penetrating Epoxy Sealer at
I haven't used this stuff, but it seems like it'll do the trick.
I would remove as much of the damage as possible and install supports for
the edge of the new wood. Unless the damage is extensive under the wall it
is not necessary to remove it. Protecting the new wood from water can't hurt
but the key is to keep the water in the shower and drain.
Absolutely! I will be re-sealing the shower door frame, where the tile
meets the door and around the base, plus anything that doesn't look
100%. I plan on removing the source of the problem before using the
I just used some on some wood next to my back door. They aren't kidding
with their warnings about ventilation! The stuff is *NASTY*. It stunk up
my whole house, and I applied it outside! Great company to deal with
You have 2 choices. You can remove the ceiling below and install
cleats, make a frame, and put a stairway up to the shower from the
room below..... That would be original, and attract attention....
On a more serious note
I have done similar repairs. You dont want to (and cant) remove all
the flooring under the shower and the wall. Instead, cut the flooring
as close to both as you can. Under that shower, start stacking
pressure treated 2x4's against the present 2x4 until you are past the
edge of the shower. Use construction adhesive and nails or screws.
You may have to use 3 or more layers. Next, place bridging 2x4's
across (from the new stack to the next joist) and toenail them. Be
sure one of them is under that wall. Stack those if needed. Be sure
to use all PT lumber. While you are stacking these 2x4's put
construction adhesive on the top edge of these 2x4s so they adhere to
the existing flooring. Don't worry about a small amount of bad floor
under the wall. If it feels better, jam a few hunks of 1x2 under the
wall, and coat it with construction adhesive so it sticks to your new
2x4 and the bottom of the wall. Apply nails or screws thru the
remaining edge of the bad flooring if you can. Otherwise, the const
adhesive should do the job.
With all of this finished, you will have a 2x4 frame going all the way
around your hole, and be sure your old wood flooring edge has a 2x4
under all cut ends, and enough 2x4 remains to attach the new wood.
Now put in insulation and apply new plywood flooring the same
thickness as the old. Pressure treated is the best for a bathroom.
Then apply floor filler or epoxy to the edges of the old (bad)
flooring to level it.
Finally, remove the toilet, mouldings, and rip up all underlayment in
the whole room, and cover the whole floor with new underlayment at
least 3/8" thick. Apply new flooring, replace toilet, and apply
moulding around the walls.
If this was my house, I'd replace all the particle board around the
toilet flange with the PT plywood too, or maybe remove all the
particle crap and redo the whole floor completely (Particle board is
good for starting bonfires, and little more).
PS Underlayment must be nailed or stapled every 2.5 to 3 inches on the
edges and every 5 or 6 inches in the middle.