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Bathroom Sub-floor Mess: See Pics

4001 Views 27 Replies 7 Participants Last post by  LittleMissDIY
So my first project in my lovely almost 100 yr old home is my half bath on the main floor. It was certainly unplanned. I went in to use the bathroom only to notice the toilet had sunk into the sub-floor (luckily it was only partially and the toilet was not in the basement, even though that probably would have been painfully funny). Apperently there had been a leak and now my sub-floor is rotted :thumbdown: (at least that's all I am hoping is rotted, fingers crossed my joices are not).

So here is my plan:

tear up tile (already partially done :thumbup:)
tear out sub-floor while praying the joices are fine
replace rotted sub-floor
lay down lumen (i hope that's how it is spelled)
lay down slate tile
remove wall paper
Paint (NO MORE PINK!!)

I hope I have it all covered. This is my first time doing anything like flooring and really the only remodel background i have is removing a ceiling with my grandparents. I would really appreciate feed back and other ideas and most definitely tips, such as laying the tile and cutting it and laying the sub-floor as well. Also, I am very unsure of making the circular cut in the tile for the toilet. I know slate is hard to work with and breaks easy.

Oh and here are some pics:

Idk if you can tell but the toilet is kinda side ways

This is my very girly pinkish tile

And this is my rotted sub-floor, which smelled aweful when I pulled up the tile.
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You may be lucky----that 'wood' under the toilet? Is it dissolving into saw dust?

Looks like the floor was laid wrong many years ago---

Remove that layer and let's see what's under it----could be 1x6 solid wood or might be another layer of floor covering---

General instructions---1)floor joist (strong enough to support natural stone) more on that later.
2) Subfloor--in 1950s and before--1x6 solid wood--Plywood in newer structures
3) additional plywood to isolate the solid wood from the tile.(solid wood moves to much and can cause tile failure.
4)tile backer--usually 1/4" cement board--set into thinset like a giant tile and nailed or screwed--
sometimes--a membrane like Ditra,by Schluter
5) tile or stone set into Modified thinset (if a membrane is used see what the manufacturer recommends)
more like multch... not quite as thin as saw dust... In the rest of the home there is original hardwood which is just on top of the joist, I can see my basement from my dining room from a gap between the planks. I can also post a photo of under the floor from the basement.
That would help---as long as the bath floor is a wreck---take a hammer to the worst area and 'dig' a hole--let's see what is under there!
these are from the basement... plus one from the bathroom, you can see the top of the joist, its a little messed up but the rest of it seems good but wont know for sure until we rip all of it out... it looks like they put the plywood on top of a solid wood floor


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You will have some wood to repair---when it's stripped of the flake board (OSB) you should be able to replace any 1x6s then top with 1/2 or 3/4 inch bc plywood---avoid the OSB--it falls apart when wet--
Other than the toilet seat appears loose that requires tightening at the plastic bolts, what I see is some old floor over older floor. For one simple reason, that the upper layer is to strength the 1x6 (lower) layer. The wax ring appears to have been leaking slowly over quite some time, but nothing to alarming IMHO.

My suggestion for you - if you want to refresh that floor:

*** before you start, please make sure you are wearing a mask and protective gear, and have ample ventilation via a circulating fan or window ***

1) Drill some pilot holes from the crawl space side to indicate clearly the where the joists start and end.
2) Get a reciprocating saw and cut off the existing 1x6s.
3) Follow the protocol and install PLYWOOD subfloor (rather than OSB)
4) Continue and finish the tile floor installation per the normal installation protocol.
5) Reset the toilet per the normal protocol.
6) Take a poop and rest your buns!

Okay, other than that #6, I think you get my drift on the flooring.

Then, after you are done with the floor work, you could begin removing the wallpaper. If the wallpaper is tough to remove because its age, just remove the drywall and start over... The key here is to be sure there is no LEAD by way of LEAD TESTING before begining any "disturbance" to the possible lead paint layer(s) - kits are available in big box stores.

Hope this helps.
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If you haven't done so already, stuff a big rag in the drain pipe to stop any more sewer gases from getting into your house.
Well we have all the tile up and we know exactly where the joists are... we are working on getting the base boards off next and tomorrow we are pulling up the rest and taking down the wall paper... i have taken down wall paper before so that is nothing new :)
Keep us posted---Go to the tiling section here and read some of the older threads----

You will want to check the 'deflection' of your floor system before you get your heart set on slate--If the floor joists are to weak,the slate may crack---read up on deflection--come back and someone here will run a deflection chart for you.
You al ready by the looks have way under sized floor joist (judging by the picture they look like 2 X 6's) if it's an old house they may even be spaced around 24" apart, which is way more then it should be to support tile.
Slate by far is one of the most poris and brittle natural stones.
Last stone I'd ever want in a bathroom or any wet area.
actually in the basement pictures you can see the joists are only about a foot apart.... as for their size i have no clue but i can find out when i go to the store :) and I am going right now to look at that deflection thing....
also how do i determine the deflection??? havent found anything saying how....
also how do i determine the deflection??? havent found anything saying how....
technically, idk. but if you can feel ANY kind of movement in it while walking on it = too much.

my kitchen (old house i bought in march) has large tiles on the floor. the floor feels solid. but the grout is all loose in places.
well the floor feels solid other than in the spot where the OSB was rotted... the tile in that bathroom is through out the house (BLEH!) and the grout is coming out but from what i understand the tile is pretty old and hasnt been regrouted before
well the floor feels solid other than in the spot where the OSB was rotted... the tile in that bathroom is through out the house (BLEH!) and the grout is coming out but from what i understand the tile is pretty old and hasnt been regrouted before
If I got what you said correctly, your floor joists are on a 12" OC build-out? Also, your joists are (at least) 2x8s? If so, you should have nothing to worry about.
well. you do have to post the joist size and length. you are going to be asked that, again. just go in the basement and measure. they are probably 1 3/4" x 7 1/4" x ??
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So you have 2x10 joists.

How far apart spacing between the joists?
they are a foot apart... i have no clue how long but i do have pictures.... the bathroom has a ton of posts.... i dont think deflection will be to bad since there are 4 posts for just this bathroom.... my stepdad thinks the previous owners screwed something up then hired someone to fix it



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