Bathroom Flooring
January 5, 2005 9:05 AM Subscribe
Bathroom tile/subfloor question. -->
I'm laying new tile on the floor of my second-floor full bath. I removed the existing tile (12-inch squares, probably asbestos) and underneath that is thick ceramic or porcelin 3" octagonal tile, all very sound and undamaged (other than covered with sticky black mastic used to adhere the tiles). Underneath the tile I found about 4-5" of poured concrete before I got to a subfloor. I removed the concrete in about a quarter of the bathroom so as to expose all the plumbing. (the pipes/drains were embedded in the poured concrete). There also appear to be joists(?) above the subfloor, over which the concrete was poured (and through which cuts were made to accomodate the plumbing). The joists appear normal (about 16" OC, 2" wide) except that rather than having flat tops (that I could nail underlayment to, for instance) they all appear to have been chiseled to intentionally create "peaks." Finally, the installers were kind enough to stuff some newspaper in among the plumbing & concrete, so I know the job was done in 1948.
To install the tile, do I have to remove all the concrete from the entire floor, remove all these weird "joists," then take out the existing subfloor that's under them (which appears to be just loose planks, with gaps of as much as a half inch in spots), and rebuild a subfloor above the plumbing, sistering new joists off the old ones that support the existing subfloor so as to bring a nailing surface up above the plumbing?
Or can I simply repour concrete where I've removed it, apply a layer of ext.grade plywood, then backerboard, to bring it all up to the level of the existing tile floor, and then put a sheet of luan over the whole thing, on top of which go thinset and the new tile?
I also considered sistering some wood to those odd joists that sit amongst the plumbing, to give me a nailable surface above the level of the plumbing, and putting underlayment and backerboard on top of that. I'm just not sure how those joists are attached to the framing (I have not removed the wall perpendicular to the wierd joists) or why there're even there.
Thoughts/advice?
I'm laying new tile on the floor of my second-floor full bath. I removed the existing tile (12-inch squares, probably asbestos) and underneath that is thick ceramic or porcelin 3" octagonal tile, all very sound and undamaged (other than covered with sticky black mastic used to adhere the tiles). Underneath the tile I found about 4-5" of poured concrete before I got to a subfloor. I removed the concrete in about a quarter of the bathroom so as to expose all the plumbing. (the pipes/drains were embedded in the poured concrete). There also appear to be joists(?) above the subfloor, over which the concrete was poured (and through which cuts were made to accomodate the plumbing). The joists appear normal (about 16" OC, 2" wide) except that rather than having flat tops (that I could nail underlayment to, for instance) they all appear to have been chiseled to intentionally create "peaks." Finally, the installers were kind enough to stuff some newspaper in among the plumbing & concrete, so I know the job was done in 1948.
To install the tile, do I have to remove all the concrete from the entire floor, remove all these weird "joists," then take out the existing subfloor that's under them (which appears to be just loose planks, with gaps of as much as a half inch in spots), and rebuild a subfloor above the plumbing, sistering new joists off the old ones that support the existing subfloor so as to bring a nailing surface up above the plumbing?
Or can I simply repour concrete where I've removed it, apply a layer of ext.grade plywood, then backerboard, to bring it all up to the level of the existing tile floor, and then put a sheet of luan over the whole thing, on top of which go thinset and the new tile?
I also considered sistering some wood to those odd joists that sit amongst the plumbing, to give me a nailable surface above the level of the plumbing, and putting underlayment and backerboard on top of that. I'm just not sure how those joists are attached to the framing (I have not removed the wall perpendicular to the wierd joists) or why there're even there.
Thoughts/advice?
I've done tilework in a house of similar vintage, but 4" of concrete poured on the second floor is beyond anything I've encountered.
I've gotten a lot of help from the John Bridge Forum. Professional tile setters hang out there, but they're very friendly to DIY'ers.
posted by klarck at 9:46 AM on January 5, 2005
I've gotten a lot of help from the John Bridge Forum. Professional tile setters hang out there, but they're very friendly to DIY'ers.
posted by klarck at 9:46 AM on January 5, 2005
I may be able to help a little, but a few questions first. Are you in a rowhouse, and if so, what is the configuration? Either way, are you certain that the pour is reserved for the bathroom only? And w/o a clear picture of the room, why did you decide to remove the concrete to access the plumbing? Are you going for full-on replacement of that as well?
posted by Heatwole at 9:59 AM on January 5, 2005
posted by Heatwole at 9:59 AM on January 5, 2005
Damn, someone beat me to the John Bridge forum. Definitely, definitely chech out there. Also consider the Michael Byrne "Setting Tile" book, published by Taunton. That bood is considered somewhat overkill by many of the JB pros, and there's a book put out by the guy that runs those forums that's supposed to be good and I haven't tried out.
Ask there. You've got a lot of issues. Whether you can sister anything to the joists depends on how they're attached and their thickness and composition. The goal is to have an acceptable level of deflection before you lay tile. There are tools on the JB site for this, but you are a special case. :) The layout of the existing joists also will dictate whether you can just throw some plywood over the top and go or whether you need additional reinforcement. It seems like you've got two levels of structure to worry about, but it's possible I didn't understand the question well enough. You will want to lay tile on backerboard, not on luan if you have the choice. Plywood is an acceptable surface in some circumstances, but backerboard is usually preferred as I understand it
I'll have to keep my eye out for your question; sounds interesting.
posted by RikiTikiTavi at 9:59 AM on January 5, 2005
Ask there. You've got a lot of issues. Whether you can sister anything to the joists depends on how they're attached and their thickness and composition. The goal is to have an acceptable level of deflection before you lay tile. There are tools on the JB site for this, but you are a special case. :) The layout of the existing joists also will dictate whether you can just throw some plywood over the top and go or whether you need additional reinforcement. It seems like you've got two levels of structure to worry about, but it's possible I didn't understand the question well enough. You will want to lay tile on backerboard, not on luan if you have the choice. Plywood is an acceptable surface in some circumstances, but backerboard is usually preferred as I understand it
I'll have to keep my eye out for your question; sounds interesting.
posted by RikiTikiTavi at 9:59 AM on January 5, 2005
I'll have to actually read my preview, too. Sorry about the poor proofreading.
posted by RikiTikiTavi at 10:00 AM on January 5, 2005
posted by RikiTikiTavi at 10:00 AM on January 5, 2005
How tall are the joists (technical term if they're above the floor sheathing is "sleepers") on top of the subfloor? Are they embedded w/in the concrete (could it be an extra thick mortar bed?)? The whole sleeper thing is throwing me for a loop, but otherwise it sounds pretty normal for '40s construction. The subfloor construction is called 'skip sheathing', and it's okay if there's gaps between the boards.
I'd guess that the sleepers are just there to provide depth; for what reason I'm not exactly sure. But I'm just assuming they're not structural; if I'm correct, and I offer no guarantees, you can do pretty much whatever you feel like to get your new tile floor in.
posted by LionIndex at 10:13 AM on January 5, 2005
I'd guess that the sleepers are just there to provide depth; for what reason I'm not exactly sure. But I'm just assuming they're not structural; if I'm correct, and I offer no guarantees, you can do pretty much whatever you feel like to get your new tile floor in.
posted by LionIndex at 10:13 AM on January 5, 2005
I've no suggestions, but one question: What on earth is the point having sleepers and concrete? And especially why would this be done on the second story? It seems absolutely bizarre.
posted by five fresh fish at 10:26 AM on January 5, 2005
posted by five fresh fish at 10:26 AM on January 5, 2005
What on earth is the point having sleepers and concrete? And especially why would this be done on the second story?
That's what's getting me! Did they lay down the sleepers and then encase them in concrete? WTF? As far as why this would be done on the 2nd story, it's probably all about having a level floor and whatever they needed to achieve that, they did.
Perhaps the original flooring in the room was wood, so sleepers were installed originally to bring the floor up to the level of other rooms in the house; or maybe they just did the thing with the pipes running through the sleepers all over, like a continuous plumbing/mechanical/electrical chase for the whole house. At one point, maybe they decided that they wanted a tile floor in the bathroom instead of wood, so they poured the concrete float to get a level, stable tile surface, and chiseled the tops of the sleepers down to allow for adhesion between the float and the tile, rather than ripping out all the sleepers and starting over to get a consistent floor surface (which for tile, they'd have to put sleepers back in, then another subfloor, then whatever kind of substrate they wanted for the tile (slipsheet, float, thinset, etc.)).
posted by LionIndex at 10:51 AM on January 5, 2005
That's what's getting me! Did they lay down the sleepers and then encase them in concrete? WTF? As far as why this would be done on the 2nd story, it's probably all about having a level floor and whatever they needed to achieve that, they did.
Perhaps the original flooring in the room was wood, so sleepers were installed originally to bring the floor up to the level of other rooms in the house; or maybe they just did the thing with the pipes running through the sleepers all over, like a continuous plumbing/mechanical/electrical chase for the whole house. At one point, maybe they decided that they wanted a tile floor in the bathroom instead of wood, so they poured the concrete float to get a level, stable tile surface, and chiseled the tops of the sleepers down to allow for adhesion between the float and the tile, rather than ripping out all the sleepers and starting over to get a consistent floor surface (which for tile, they'd have to put sleepers back in, then another subfloor, then whatever kind of substrate they wanted for the tile (slipsheet, float, thinset, etc.)).
posted by LionIndex at 10:51 AM on January 5, 2005
To answer your question five fresh fish, the reason why I asked if he had a rowhouse is that, in the 40's the bathroom concrete was laid to mirror the bathroom next door, making construction quicker.
As an aside, while we all wait for more info, our pre-purchase house inspector who inspected our 1942 house told me that it was the last good year that a house was built in the last century. His reasoning was that the war sucked dry so many materials that building practically stopped and that when it began again, the housing codes had to change in order to not only accommodate the returning servicemen but also to address the deficit of materials. Makes sense.
posted by Heatwole at 10:58 AM on January 5, 2005
As an aside, while we all wait for more info, our pre-purchase house inspector who inspected our 1942 house told me that it was the last good year that a house was built in the last century. His reasoning was that the war sucked dry so many materials that building practically stopped and that when it began again, the housing codes had to change in order to not only accommodate the returning servicemen but also to address the deficit of materials. Makes sense.
posted by Heatwole at 10:58 AM on January 5, 2005
Response by poster: some responses: I'm in a freestanding single family home (built 1907). I have not pulled up any of the hardwood flooring that covers the rest of the 2nd floor, but I've seen one room from below when we demo'd the kitchen down to studs. It's regular subfloor/joists under the rest of the 2nd floor.
I removed what concrete I did, so the plumber could come in and take a look at what was there before I covered it up with new flooring. Strictly precautionary, done because of the age of the home and my aversion to having to tear out the floor again in five years because of mystery leaks.
I'll post a photo of what I'm talking about tonight, but the sleepers are around 3 inches tall IIRC. They were embedded within the concrete. I originally thought they were there to provide rigidity and stability to the concrete pour? But I know nothing.
Finally, I think the concrete was just the 40s version of backerboard -- a defense against water seeping down into the floor.
Please continue to muse away, and I'll check the JB forum. Thanks!
on preview:
they lay down the sleepers and then encase them in concrete?
Yes.
WTF?
Yes.
chiseled the tops of the sleepers down to allow for adhesion
that makes sense, but they seem very deliberately shaped in a peaked, tent-like manner. the photo tonight will reveal all.
posted by stupidsexyFlanders at 10:58 AM on January 5, 2005
I removed what concrete I did, so the plumber could come in and take a look at what was there before I covered it up with new flooring. Strictly precautionary, done because of the age of the home and my aversion to having to tear out the floor again in five years because of mystery leaks.
I'll post a photo of what I'm talking about tonight, but the sleepers are around 3 inches tall IIRC. They were embedded within the concrete. I originally thought they were there to provide rigidity and stability to the concrete pour? But I know nothing.
Finally, I think the concrete was just the 40s version of backerboard -- a defense against water seeping down into the floor.
Please continue to muse away, and I'll check the JB forum. Thanks!
on preview:
they lay down the sleepers and then encase them in concrete?
Yes.
WTF?
Yes.
chiseled the tops of the sleepers down to allow for adhesion
that makes sense, but they seem very deliberately shaped in a peaked, tent-like manner. the photo tonight will reveal all.
posted by stupidsexyFlanders at 10:58 AM on January 5, 2005
Since you've gone this far down the rabbit hole, why not add some sort of radiant heating? Should be a nice re-sale value.
posted by Heatwole at 11:13 AM on January 5, 2005
posted by Heatwole at 11:13 AM on January 5, 2005
Response by poster: I thought about that. We put it in our kitchen and really like it. Be nice to get rid of the cast iron radiator.
posted by stupidsexyFlanders at 11:17 AM on January 5, 2005
posted by stupidsexyFlanders at 11:17 AM on January 5, 2005
What fixtures are you planning for over top of the floor? Most likely the joists were put in originally to support heavy fixtures. You may want to add reinforcement just to be safe.
I'd pour a mud floor over what you've got, lay the tile on the mud. Less work, much more sturdy and permanent. Backerboard is one of those modern inventions that is supposed to be better but isn't, imo.
posted by clubfoote at 11:19 AM on January 5, 2005
I'd pour a mud floor over what you've got, lay the tile on the mud. Less work, much more sturdy and permanent. Backerboard is one of those modern inventions that is supposed to be better but isn't, imo.
posted by clubfoote at 11:19 AM on January 5, 2005
Response by poster: Putting back in the cast iron clawfoot tub that I pulled out to do the demo. (plus wall sink & commode)
pour a mud floor
How much thickness would be required on top of the existing tile? Because I don't want to raise the height of the floor too much. The only thing on the tile before was 1/8" asbestos tile.
posted by stupidsexyFlanders at 11:24 AM on January 5, 2005
pour a mud floor
How much thickness would be required on top of the existing tile? Because I don't want to raise the height of the floor too much. The only thing on the tile before was 1/8" asbestos tile.
posted by stupidsexyFlanders at 11:24 AM on January 5, 2005
How much thickness would be required on top of the existing tile? Because I don't want to raise the height of the floor too much. The only thing on the tile before was 1/8" asbestos tile.
I'm a bit confused, I thought from reading your original post that you removed all the tile. Now I'm thinking you left the old underneath tile down. Personally I'd take that stuff up, and pour a brand new mud floor over top to the level you want your new floor to be at. It seems like more work at the beginning, but the hard part of what your doing is floating the mud level, and if you've never done that before, trying to level to an existing old tile installation will be very frustrating. Its much more forgiving to float the whole floor, you can smooth it out over the whole surface and then not have to worry about trying to match up to a nearly 100 y/o floor that has probably settled out of level anyway.
With that clawfoot, I'd make sure the joists are still sturdy, maybee add some additional bracing if you can. It would be a shame to do all this work and have it become unsound 10 years down the road.
posted by clubfoote at 11:40 AM on January 5, 2005
I'm a bit confused, I thought from reading your original post that you removed all the tile. Now I'm thinking you left the old underneath tile down. Personally I'd take that stuff up, and pour a brand new mud floor over top to the level you want your new floor to be at. It seems like more work at the beginning, but the hard part of what your doing is floating the mud level, and if you've never done that before, trying to level to an existing old tile installation will be very frustrating. Its much more forgiving to float the whole floor, you can smooth it out over the whole surface and then not have to worry about trying to match up to a nearly 100 y/o floor that has probably settled out of level anyway.
With that clawfoot, I'd make sure the joists are still sturdy, maybee add some additional bracing if you can. It would be a shame to do all this work and have it become unsound 10 years down the road.
posted by clubfoote at 11:40 AM on January 5, 2005
Most likely the joists were put in originally to support heavy fixtures.
The joists below the subfloor? Yes. The little 3" guys encased in concrete? Nuh-uh. 3" of wood and concrete on top of your subfloor probably isn't really doing anything structurally other than adding dead load.
How much thickness would be required on top of the existing tile? Because I don't want to raise the height of the floor too much. The only thing on the tile before was 1/8" asbestos tile.
Depending on the size of the tile you're installing, you'll need from 1/2" to 2" of mud float for tile. If you go this route, you'll most likely be taking out the entire floor of the bathroom and starting over from the subfloor up, not adding on to what you've already got. In this case you'd be pouring about 3" of mud to replace the sleeper/concrete height, which would also allow you plenty of room to run radiant heating tubes through the pour.
posted by LionIndex at 11:45 AM on January 5, 2005
The joists below the subfloor? Yes. The little 3" guys encased in concrete? Nuh-uh. 3" of wood and concrete on top of your subfloor probably isn't really doing anything structurally other than adding dead load.
How much thickness would be required on top of the existing tile? Because I don't want to raise the height of the floor too much. The only thing on the tile before was 1/8" asbestos tile.
Depending on the size of the tile you're installing, you'll need from 1/2" to 2" of mud float for tile. If you go this route, you'll most likely be taking out the entire floor of the bathroom and starting over from the subfloor up, not adding on to what you've already got. In this case you'd be pouring about 3" of mud to replace the sleeper/concrete height, which would also allow you plenty of room to run radiant heating tubes through the pour.
posted by LionIndex at 11:45 AM on January 5, 2005
Response by poster: To be more clear, over about 3/4 of the floor, I only removed the asbestos tile, and the old ceramic tile underneath is still there, and sound. In the remaining 1/4, I knocked off the ceramic tile and removed all the concrete, to expose the plumbing (and those sleeper joists).
posted by stupidsexyFlanders at 11:57 AM on January 5, 2005
posted by stupidsexyFlanders at 11:57 AM on January 5, 2005
then take out the existing subfloor that's under them (which appears to be just loose planks, with gaps of as much as a half inch in spots)
Wouldn't the concrete flow out through those gaps?
I'm now thinking that the concrete was poured simply 'cause it was a dirt-cheap way of leveling the floor and provided an as-ready surface for tiling. The short stubs probably made that task easier, perhaps letting them pour & trowel in manageable sections.
Old houses are definitely puzzling.
posted by five fresh fish at 12:38 PM on January 5, 2005
Wouldn't the concrete flow out through those gaps?
I'm now thinking that the concrete was poured simply 'cause it was a dirt-cheap way of leveling the floor and provided an as-ready surface for tiling. The short stubs probably made that task easier, perhaps letting them pour & trowel in manageable sections.
Old houses are definitely puzzling.
posted by five fresh fish at 12:38 PM on January 5, 2005
The partial patching of the material supporting the tile sounds like a job for a lightweight, self-leveling gypsum topping. This material can feather to nothing, which a "mud" setting-bed can not. (I come from the mud-set-best-for-floor school but that does not sound like the best approach here.)
A shame you can not work with the existing tile -- or can you... I'll be checking back for the photo.
The "joist with concrete" condition sounds very european. In Paris, a typical older building will have wood joists with a mix of rubble and a sandy mortar between (the closest comparison in final texture would be a mud setting bed. Think of a really dry mortar mix.) Tile is then laid atop. Plumbing rarely, if ever, runs in the space between ceiling and floor below. Most older buildings have no "ceiling" per se -- what in French is a "faux plafond" or "false ceiling".
A european toilet has a horizontal discharge (no wax seal at the floor) so all waste lines run above the floor level. This makes for a lot of exposed pipes, often on the exterior of the building. It's weird but one becomes accustomed to it.
posted by Dick Paris at 1:01 PM on January 5, 2005
A shame you can not work with the existing tile -- or can you... I'll be checking back for the photo.
The "joist with concrete" condition sounds very european. In Paris, a typical older building will have wood joists with a mix of rubble and a sandy mortar between (the closest comparison in final texture would be a mud setting bed. Think of a really dry mortar mix.) Tile is then laid atop. Plumbing rarely, if ever, runs in the space between ceiling and floor below. Most older buildings have no "ceiling" per se -- what in French is a "faux plafond" or "false ceiling".
A european toilet has a horizontal discharge (no wax seal at the floor) so all waste lines run above the floor level. This makes for a lot of exposed pipes, often on the exterior of the building. It's weird but one becomes accustomed to it.
posted by Dick Paris at 1:01 PM on January 5, 2005
Response by poster: Dick, hard to tell if this was the effect of age, but the european model seems like what this was -- definitely a mixture of rubble and a sandy mortar, so dry that I was able to unwrinkle and read a newspaper page that I found in it, along with various matchbooks, wood scraps, plumbing debris, etc.
sounds like a job for a lightweight, self-leveling gypsum topping
It's a depth of like four inches, you understand that, right? And it's about a quarter of the total floor sq footage. Is the gypsum mix appropriate here?
A shame you can not work with the existing tile
If by "work with" you mean covering with a membrane and tiling on top of that, someone suggested as much on the JB forum I posted to at the suggestion upthread.
posted by stupidsexyFlanders at 1:15 PM on January 5, 2005
sounds like a job for a lightweight, self-leveling gypsum topping
It's a depth of like four inches, you understand that, right? And it's about a quarter of the total floor sq footage. Is the gypsum mix appropriate here?
A shame you can not work with the existing tile
If by "work with" you mean covering with a membrane and tiling on top of that, someone suggested as much on the JB forum I posted to at the suggestion upthread.
posted by stupidsexyFlanders at 1:15 PM on January 5, 2005
This thread is closed to new comments.
posted by bh at 9:33 AM on January 5, 2005