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damaged subfloor by tub

9K views 47 replies 5 participants last post by  Klawman 
#1 · (Edited)
I would greatly appreciate suggestions as to what to do about this.

I found the damage when I pulled back a section of baseboard that abutted the lowest tile along the head of the shower/tub wall. It had some black mold or something on its surface.

When I pulled the base board back the lowest wall tile came loose. I was able to extricate it without damaging the tile and hope to glue it back in place.

The first thing I found was that a nail driven through the hardie backer. The board was crushed and the chipboard under it was broken up. The fibres of the exposed part of the chipboard was loose. (The tile didn't run all the way up against the wall.)

The crushed area of hardie board came right up along with pieces of the underlaying chip board as well as parts of chipboard that had been between the edge of the tile and inner wall.

What should I do?

A. I believe that the hardie backer should be attached to the chipboard with thin set. If so, should I be able to cut the hardie board back farther than the chipboard so as to offset any seam? I would do so by cutting a line just the depth of the hardie board.

B. If the hardie board cannot be be removed as in A, I guess I have no choice but to go in though the first floor ceiling. Should I do this regardless to better assess any leaks or problems beneath the tub?

I would like to affect the repair with as little expense and work as possible, but want it done reasonable well.

Pictures and a schematic are uploaded.
 

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#4 ·
If you want this done right your looking at a total gut job.
The floor and the walls shot.
Also going to have to add some blocking under that floor to support it.
 
#5 ·
Not what I wanted to hear, JoeCaption, but pretty much what I thought may be the case. By a total gut job, I guess you mean tearing up the tiles, hardie board, and chipboard and then replacing or repairing joists as needed. Do you think the tub has to be pulled? I was thinking that I can access what is going on there, and with the plumbing, if I cut into the ceiling below.

How did you conclude that the walls are trashed. I don't think they can be seen in those pics and they look okay from what I can see - so far.

Possibly your experience and the fact that water that got into the chipboard lilkely seeped down the wall.
 
#7 · (Edited)
Three things.

I won't be climbing under the house. I wish. This is on the second story of stucco house built on a slab, which means I have to open some walls or a ceiling to see better what is going on.

I think I see what you mean by the water stains, the whitish mineral stains. I have tested them with by trying to shove a screwdriver into the wood and cannot find any dry rot, which is not to say that I shouldn't open the ceiling up below the problem area to check things more carefully.

Lastly, I erred when I said that the joists run parallel to the tub. I was looking at what I call a block. The joist in the photos runs perpindicular to the tub and where the block appears to be a 2X7 the joist looks to be a 2x8. (Romex that isn't viewable in those pictures runs under the 2X7)

Did I say that I appreciate you giving me your advice? Thank you.
 
#8 ·
Klawman---That is a frequent sighting----a fix can be done without to much work--

If you own a Multi-tool you could have that fixed in a few hours.

first cut back the hardi board 2 to 3 inches from the tile---remove that--

Then cut the OSB out an inch or two from the remaining backer board----

You need a screwing surface---so leave a border at the tub,also--

Using a strong builders adhesive ,like PL Premium, glue in some 2x4 blocking to support a new piece of subfloor---Pin it into place with screws---

Add the new sub floor using glue and screws.

Replace the missing Hardi board---use some thinset under it---

Replace the tile----

That will do----until it's time for an entire bath floor----a magnetic shower curtain might help prevent that "escaping water' damage---
 
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#9 ·
Klawman---That is a frequent sighting----a fix can be done without to much work--

If you own a Multi-tool you could have that fixed in a few hours.

first cut back the hardi board 2 to 3 inches from the tile---remove that--

Then cut the OSB out an inch or two from the remaining backer board----

You need a screwing surface---so leave a border at the tub,also--

Using a strong builders adhesive ,like PL Premium, glue in some 2x4 blocking to support a new piece of subfloor---Pin it into place with screws---

Add the new sub floor using glue and screws.

Replace the missing Hardi board---use some thinset under it---

Replace the tile----

That will do----until it's time for an entire bath floor----a magnetic shower curtain might help prevent that "escaping water' damage---

That is pretty much what I had been thinking can be done, unless the damage is more extensive than it looks from the small hole opened up. Especially given it is located in a corner which is never stepped on.

By a multi tool I suppose you mean something like a rotozip. I have a Dremel, which is like a rotozip on tranquilizers, but it should get this small job done. I may even treat myself to a sawsall, which is something I could have used long ago, just to make it easier to get in close to the tub and walls.
 
#17 ·
Believe it or not---Harbor freight makes a good one for about $40 on sale----nice tough tool and the blades are relatively cheap----

If you want a name brand--Bosch makes a good one----Dremmel over heats---
 
#19 ·
Thanks Carrwood and oh'mike. I am getting into it now. My buddy at HD quietlty turned me on the Harbor Freight for a Multi Tool and elsewhere have seen some good reviews of it and especially for the price. I cut a piece out of the backer board with my old Dremmel to compare with today's backer board and make sure I get the same stuff and am off to he HD and perhaps Harbor Freight.
 
#21 · (Edited)
I picked up the Dremmel model because I wanted to get the job done and time and gas is worth a few bucks. That and the brand may last a bit longer. Forgot what Mike said about the Dremmel overheating, but I doubt I would use any brand, even Harbor Freights, enough to wear one out.

I tested it on the Hardie Backer Board and it worked fine. Got little done as I noticed that one of the hold down bolts for the toilet in that BR was sheared off. So I pulled the toilet and replaced the bolts and wax ring. I was concerned that their may have been some leaking around there but it looks good.

I only had a few minutes to experiment with the Multi Tool and it is slick. I only wish they had a blade to cut tile, but there is one for the old basic Dremmel.
 
#23 ·
I got a Dremmel "Carbide Rasp" for taking the lumps of grout down to the level of the tile suface. The kid at HD said I could do what I needed with the free sanding attachment that came with the Dremmel. He was right, the course paper took it down real quick.

I saw the carbide bits for cutting grout. There are two thicknesses. 1/16 and 1/8. Down the road I will need one, but not yet and I may get one on sale.

Meanwhile I got a plunge blade for metal/wood, another wood plunfe blade, and a wood blade that is supposed to emulate a small circular saw. It was a kit for a good price and I will use them..

A kid gave me an idea on how to reglate my depth by placing several layers of tape on the side of the blede to prevent me from cutting down into the OSX when I cut the Hardie Backer.

Meanwhile, why I am in there making a mess, I pulled the toilet and am basically replacing its working parts, seals, and wax ring. I took it off to ensure that the subflooiring on that part of the BR was dry. Enough of that. I got some help with this on the DIY chatroom plumbing board.
 
#24 ·
I got sidetracked with some plumbing issues. First I pulled and replaced the wax rings for the toilet in the BR - which allowed me to inspect the flooring around the flange. Then I spent some time playing with the kitchen sink, which had several problems of which all are waiting for free parts from Price Pfister.

I did some neat cutting with that multi tool and confiremd where that the jouists under that upper Bath Room floor run parallel to the tub. Also, to do the job well , I figured out that I should remove one other tile running along that wall AND I need to access things from underneath. That means gutting the first follor ceiling and it just so happens that means removing a ceiling/wall cabinet in the laundry room. The nice part about that is I needn't be to particular about my drywall patch job as it will be covered when I replace the cabinet.

For now my family insists I take a day off.

I love that multi tool. Thanks guys. I need to save money and do things myself. Yesterday, my son got his acceptance to medical school and we need every penny we can hustle up. (I know I am bragging but I thought the kid was dreaming the impossible dream when he started applying.)
 
#25 · (Edited)
Hacking away

Been doing a few other things, why I pondered if I wanted to try to fix this through the first floor ceiling. I decided not to because there is a large wall cabinet hung just under the area and I din't want to remove it if I didn't have to.

The truth is I didn't really understand oh'mikes suggestions until I went back and read thim this morning in the light of what I had observed from poking in this corner and that. Because the water damage was a tad more extensive than I thought, I decided that I had to remove the next tile in line along the tub.

I took some pictures since I have a qustion about the manner in which the tiles were laid.

I used that multi tool to remove the base board, by first removing the grout between the board and tile and then using the flush cut metal blade to get behind the boards and cut the brads. One reason I went to the bother is I wanted to see how easy it would be to revove the bb all around the bath room, since I may want it sitting on the tile.

If you will take a look at the picture of where the second tile was removed, is that trowled stuff thinset? It looks like the gout to me. But a trace of it was under the corner tile that I recall. I believe white stuff was under that tile.

The joists appear to be 2x8 on 16 centers spaced with 2x10 blocks. The blocks are even with the top of the joists but drop below the joist bottome by 2"

Maybe I will get this done tomorrow, when I get back from the range. Thanks for the help.
 

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#26 ·
White thinset----many tile setters use white----the dark colored thinset is more difficult to clean off the edge of the tiles (squeeze out)

I see you are enjoying that Multi tool------save all worn out blades to use as scrapers---caulk cutters----thinset removers--

My assistant uses the angle grinder to cut new teeth into dead blades for removing thinset squeeze up---
 
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#27 ·
White thinset----many tile setters use white----the dark colored thinset is more difficult to clean off the edge of the tiles (squeeze out)

I see you are enjoying that Multi tool------save all worn out blades to use as scrapers---caulk cutters----thinset removers--

My assistant uses the angle grinder to cut new teeth into dead blades for removing thinset squeeze up---
I here you on saving the old blades. so far I have used up two bladesI think it will be some work taking that thinet down. I plan on using the dremel rasp blade for that.

This job has grown, but not gotten out of hand. What you would knock out in 2 hours is will take me a total of about 20 (to get all the bad wood out I am removing a total of 4 tiles). I think my fix will outlast the rest of the floor.
 
#28 ·
Those little repairs do take time---trying to find a pro to do a repair is very hard to do----

I seldom do repairs----to much time is involved----but I do go to look---

an angle grinder is a handy tool for jobs like yours----with a diamond blade-----I'm not suggesting you buy one---but they are well worth the $25--or so for a cheap one----fitted with a wire brush--it would be worth the money if you only used it to clean the bbq grill----
 
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#29 ·
Those little repairs do take time---trying to find a pro to do a repair is very hard to do----

I seldom do repairs----to much time is involved----but I do go to look---

an angle grinder is a handy tool for jobs like yours----with a diamond blade-----I'm not suggesting you buy one---but they are well worth the $25--or so for a cheap one----fitted with a wire brush--it would be worth the money if you only used it to clean the bbq grill----
The tool rental guy at HD suggested one of those for cutting a couple of tiles instead of renting a wet saw. I may look into getting one at Harbor Freight instead of renting one for $35 for 4 hours.

I can see how a pro would lose his ass doing a small job like this, if he was going to charge for the time it takes to due the job right.
 
#32 · (Edited)
Cutting 26" straight line in tile

I have to cut two new 13" tiles with a neat straight line. Can that be done on a 10" table saw with the right blade/wheel? Should I be able to mount a grinding wheel on it. I would lay down a piece of plywood to protect the table top.



Not mine but I have one.
 

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#33 ·
See if an 8 inch diamond blade will fit the arbor---any dry cut often gets hot and chips the heck out of the cut-----

Also---Lowes used to make cuts for customers for a couple of bucks---call and ask if they still do it----

Any dry cut
 
#36 ·
See if an 8 inch diamond blade will fit the arbor---any dry cut often gets hot and chips the heck out of the cut-----

Also---Lowes used to make cuts for customers for a couple of bucks---call and ask if they still do it----

Any dry cut
Having it done at Lowes it the ticket. Maybe if I just drive around the neighborhood I will spot a guy doing some tiling work and give him a few bucks to make those two cuts.

I just posted some final plans.

I am kind of glad I opened up up a bit. Now I can see that it is nice and dry under there.
 
#37 ·
That little job sure has grown up!

Wet saws come in all prices----even the cheapest one will do a passable job,if you decide to purchase one---
It sounds like I could save a lot of money and pick up some DIY tools at Harbor Freight. I may just finish the framing, subfloor, and backer board and pay some guy to do the four tiles. The guy across the street is having a $20,000+ water damage job done right now by a buddy that has a restoration company and I could probably work a deal
 
#38 ·
Potlatch Oxboard

I am back after having to take a few days off and still can't touch the floor for a couple of days. Meanwhile, I looked at what they ripped up out of the neighboors bathroom, which is having some extensive repoairs done at the expense of some insurance company.

The subfloor is 23/32" tongue and groove Oxboard Strud-I-Board manufactured by POtlatch (an OSB product). When I measure it, I swear it is a full 3/4" and I want to match the depth of the present floor, but am wondeing if the 1/32nd differential is due to swelling of the floor.

I will probably only be replacing an 18x16" section of subfloor in the affected corner and so far doubt that I will come up against a tongue and roof seam. Before buying material, I will cut the existing board to see just what I have, but assuming no t&g seams aew involved should I just use vanilla 23/32 OSB from HD or pay a premium for sturdiboard? If I use regular OSB sheathing I can get a piece of scrap for a couple of bucks, but will spend the $36 for floor rated OSB if it is needed?

Would it be better to use 23/32" plywood in that one corner? Some guy at the HD was telling me to use CDX. Unless I know the indivicual pretty well I have little faith in guys at HD.

I will screw both the subfloor and the 1/4" HardiBaord.

I am wondering if I use either if I need to seal the edges where cut. Some OSB is supposed to be sealed for moisture.

I live in Southern Cali about 15 miles inland of the ocean and on the inland side of coastal mountains so weather is mild.
 
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