Rebuilding? sleeper floor to tile bathroom [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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03-08-2005, 05:26 PM
Hi all, Jeff here ... I've been lurking here for a few weeks... reading tons of old threads, many informative, some just entertaining :)

I'd like to tile a small bathroom floor (24' sq. w/ toilet and pedestal sink only) with 3/4" (4mm thick) glass mosaic tiles. I haven't actually seen the tile samples yet, but that's the current theory.

The original floor was vinyl linoleum glued over what appeared to my untrained eye to be 3/4" SLC on 3/4" OSB, no wire or mesh or anything in the SLC (I removed it). The whole floor is raised, I think I've seen you guys call it a sleeper floor (my first guess was false floor). The OSB is nailed, no glue to 2x6's spaced 16" o.c. The floor underneith the sleepers appears to be 3/4" OSB again, probably single layer but I can't tell for sure yet, don't know about the nailing/gluing, etc either.

I decided to go ahead and remove the OSB as it creaked against the sleepers and that simplifies adjusting the toilet flange to the finished floor height, if I end up just going over the existing sleepers, I had expected to use two sheets of plywood, maybe 3/4" + 1/2" depending on what's needed. But never mind that, I'm here to see what you guys recommend.

Once I completely remove the OSB, I'll be able to see where the toilet drain goes into the subfloor OSB and measure at the hole. The subfloor is sitting on I-beam joists 16" O.C. and 10" high (don't know the make/model, I had another ceiling torn open recently and saw them but already patched that up before thinking about this project), maximum unsupported span is 16' (worst case, there is a wall below, but I don't know whether or not it is load bearing), the bathroom is right against the main load bearing wall and extends out a maximum of 4'.

The sleepers themselves don't seem incredibly sturdy (with no OSB above them, they have some give when pushed from the side without too much force), but not having any framing background I don't know how solid they should be.

The floor meets a carpet at the doorway so the finished tile floor probably needs to be anywhere from the original linoleum height to +1/2" or so without causing any transition issues. This means 6" + 3/4" + 3/4" = 7.5" minimum off the real subfloor.

So what's the right way to build this floor? I've read a bunch of the various recommendations for different situations here, but as I took my floor apart the methods that seemed obvious kept changing (with little experience I didn't have good idea what I was dealing with until the floor was somewhat taken apart).

Sorry, that ended up long, but I wanted to jumpstart things by telling you as much as I had ready regarding the details.

BTW this forum is AMAZING! I participate in numerous online forums for various interest areas and this one appears to have incredibly helpful and more importanly knowledgable contributors and a very low signal to noise ration.


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John Bridge
03-08-2005, 07:33 PM
Hi Jeff, Welcome aboard. :)

Gotta tell you that back in the day I lived over by Silver Lake. Way back in the day. I have trouble recognizing the area now. :)

I would like to know what's actully under the first layer. I'm not sure what a sleeper floor is. I'm assuming there are other joists down underneath? In any case, I don't think you'll have severe problems getting a little floor like that up to snuff. The bigger issue will be the glass mosaics. I would not recommend them for a floor of any sort. :)

03-08-2005, 08:37 PM
Maybe it's not called a sleeper ;) You guys tell me. Here are the original floor specs a bit more concisely that my long explanation:


6) Linoleum
5) 3/4" SLC (or similar)
4) 3/4" OSB
3) 2x6's (16" O.C., nailed to OSB below, max length ~4')
2) 3/4" OSB
1) I-beam (10" high, 16" O.C, 16' maximum span)

Here's the shape of the room, joists run vertical through the diagram (not to scale, but general shape, * = toilet, + = pedestal sink):

| ** |
Door ** | Total area = 24' sq.
| ++ /

Linoleum + SLC + OSB is now gone (layers 4-6), I'm staring at the tops of layers 2 and 3.

Tell me about the mosaic tile issue(s). Manufacturer listed them okay for floors, but obviously okay is not necessarily same as good idea and I'm sure you guys know the real-world implications. This is a low-traffic, no shoes, bathroom. It this an absolute no-no or a trade-off? What are the expected problems?

Regardless, I will need to prep the floor for some kind of tile.

If forgot to mention before that I'm considering electric radiant floor heat (wire method rather than mat just to trim cost, my time is free!), initially I'd been interested in SLCs to provide a nice cover for the wires, but that was before I realized that the existing floor alone probably wouldn't handle tile and decided to start fresh.


03-11-2005, 02:40 AM
Advice anybody?

I'm curious about the best way to build up the floor AND the issue of using glass mosaics for a floor like this. My wife really likes the tiles and I think I've seen others here reference doing something similar, but John said bad idea so I'd like to know the why, tradeoffs, etc.

I've attached an image of the floor in its current state. The 2x6's are nailed above the actual joists. One of the joists (and the 2x6) is severed for the toilet drain. Finally, the outer rim is made of 2x4's affixed to the wall so the bottoms don't actually touch the subfloor. What's the best way to build this up (I open to pretty much anything I'm capable of doing)?

03-11-2005, 09:00 PM
Welcome, Jeff. :)

You got any eye-dee why they did that floor like that? Ain't never seen the like of it. :confused:

The first consideration that springs to mind is the deflection of the actual floor joist system. You may well be getting L/360 outa them engineered ten-inch joists, but without knowing what they are it's difficult to say. That would be a requirement, though.

And movement and squeaks and such with those "sleepers" (which I assume are run perpendicular to the joists) could be an issue.

Were it my floor, I'd tear out what I see in your picher. I'd re-frame that area in a similar fashion, but to a height that would allow a 3/4 inch subfloor and a mud floor of at least 1 1/4 inch. That would allow you to level and flatten everything (which I gotta believe you need some of) and have a very solid surface on which to proceed with your heating system and tile.

Framing it yourownself allows you to ensure that there is no flex or movement in any of that system, which I would do by using construction adhesive when attaching the new sleepers to the bottom subfloor and attaching the new subfloor to the top.

Yep, that's what I think I'd do there.

My opinion; worth price charged.

Oh, and I don't know diddly about the glass tiles onna floor. You'll hafta get JB to 'splain that. Ping him if he don't show up soon, eh?

03-11-2005, 11:07 PM
The rest of the house layout explains that floor construction). The "real" floor of that bathroom is level with the dining room adjacent to the right wall, but the bathroom "false" floor was built level to the platform that starts the stairs up to the next floor. The picture below should clarify the why.

The sleepers are actually nailed directly over the joists so they run parallel to them.

Since I need the final floor height to be about 7.5" - 8" above the real subfloor, I could replace the existing sleepers with 2x4's (all resting on the subfloor, no floating perimeter like now, put some plywood on top of that and then the mud floor you mentioned.

I don't know much about the mud part (I've read some here), but have John's book on the way. How deep can the mud floor be without weight issues? 2x4's + 3/4" plywood would put the mud floor closer to 3"+, could use more plywood underneath ... cost trade-off I guess.

Would you put the sleepers perpendicular to the joists or the way they are now? Any concern over the one severed joist by the toiled drain (can't tell what else was or was not done in that spot for support)? How much plywood? How deep can the mud go?


03-12-2005, 03:43 AM
Jeff - you've got it demo'd this far - any chance of expanding the project to move the door to where the sink is and vice versa? A little plumbing (Ok, a lot of plumbing), a little carpentry, a little sheetrock and Voila! - you don't need that raised floor anymore and you get your doorway off of the stairs. Almost sounds like fun even, don't it? :)


Rhode Island Flooring
03-12-2005, 06:52 AM
If I was to say...maby somone may back me up on this.. but
would you want to rip that whole step area with carpet up ? Then you could rip the existing door frame out and rebuild the door frame where the hardwood ends!!! Bigger bathroom + you can easily achive minimum deflection with some subfloor. Ill respond more according to your response. :cool:

03-12-2005, 10:32 AM
Bill --

There's a staircase going up from the platform opposite the bathroom door.

Rob --

The hardwood floored room is the dining room. For aesthetic reasons, many people don't want a bathroom directly off a kitchen or dining room. Putting the door around the corner increased the perceived space between the rooms. Probably why it was designed that way in the first place.

If this were my house, the floor plan would remain the same.

03-12-2005, 11:30 AM
Framer prolly had stair riser/tread minimums to meet which led to the raised landing which in turn begat the raised BR floor.

I'd frame in new sleepers using Simpson Strong-Tie connectors and lotsa polyurethane adhesive to the ply deck below which in turn would be well screwed into the joists below. Don't use those old 2"X6's" Jeff - too dry and will turn into kindling when nailed.

Glass tiles verrrry brittle. I'd have 3/4" T&G fir ply plus another layer of 1/2" glued over that, CBU plus tile. Or go with 3/4" T&G, mud floor, and tile.

Now this idear of mine should get that gentleman from Boerne in here with a comment or two. :complain:


Rhode Island Flooring
03-12-2005, 12:16 PM
Ok i understand clearly now. that explains the joists over sub. aka "sleeper". didnt know there was stairs there. :crazy:

03-12-2005, 08:47 PM
I'm a lot concerned about the joist you say has been "severed" where the terlit drain is. You mean they cut completely through one of them Injineered joists that's spanning the 16 feet unsupported? And no added support below? This would generally qualify as a bozo-no-no. :shake:

If that's the case, and you have no way to fix the situation, and you intend to tile anyway, I would run the sleepers perpendicular to the joists this time, screwing them well into the joists below. It ain't much, but it would give you at least a little more support for those joist ends. Wouldn't hurt to add several of those as "strongbacks" across that area even where you don't need them for joists for the upper deck. You need to be able to reach to the joist on either side of that one to do any good at all, farther would be better. Still ain't gonna git no gold star from Injineer Bob, though. :rolleyes:

My thoughts on the sleepers was to get some 2x6s and rip them to whatever height was exactly right to acommodate your subfloor, mud, and tile to make the finished floor height come out exactly where you want it.

My opinion; worth price charged.

03-12-2005, 11:23 PM
Did a bit more inspection of the joist. It isn't actually severed, a U shaped piece was cut out to make room for the drain. The bottom 4" of the joist is intact and there is a 2x4 affixed to one side of the joist running parallel.

There is a garage wall under the bathroom (to the right past the bathroom wall a bit), I don't know if it is load-bearing, but the unsupported span might only be 5'.

Not sure how to verify all of this to see if it would pass the engineers. Its a townhouse unit in a big complex, I would expect that the original builders engineered it right, but design and implementation could be two different things.

Ripping 2x6's, duh... okay, so mud height + ripped height + 3/4" = 7.5". Gotta check out the mudding story.

03-13-2005, 12:16 AM
Hi Jeff,
I personaly would not go to the trouble of mudding the floor if it were my house, But I would reframe the floor like the other post said, Run new joist opp. the existing ones (if thats the shortest span) if not then run em the other way , screw a ledger or rim joist around perimitter of room 3 screws per stud , use hangers like Mike said to attach joist and being that the bath is only 5 to 6 feet wide and you will have it locked in on all four sides with the ledger , Id just glue and shim the joist were they cross the others or in the center if they are running parrallel a couple layers of plywood and some cbu and your ready to go. unless Bob the engineer has other ideas.

just my 2cents


11-27-2011, 12:15 PM
Stumbled back in here many years later considering a fireplace rockwork redo (in a different home, state, etc). I hope digging up a very old thread isn't a problem but I thought I'd post up a photo of where this project ended.

I rebuilt the sleepers with 2x4s, adhesive, strong ties, etc and then two layers of 1 1/8" T&G (total overkill I know but it fit the level I liked and for the minimal square feet was a non-issue on price). Put electric heat wire in covered by SLC and then the glass tiles over that. Used Spectralock grout. Whole thing came out very nicely by my standards (although I did get too much thinset into the joints and had a heck of a time carving it down with the glass tiles - chipped some but worked out pretty good with a few replacements).

With all of that ... here's the after photo:

11-28-2011, 05:33 AM
Looks good, Jeff! :clap2:

Thanks for the update!

11-28-2011, 10:00 AM
You're finished already?!! That's impressive. :D

Looks like a nice little powder room, though. :)

12-18-2011, 03:52 PM
Jeff, thanks for posting your final pic- Beautiful! I am about to embark on a similar floor in an even teenier bathroom, and scouting here for info before I lay the tile. Glad to hear the spectralock worked for you- I had read this is the right grout to use for this kind of tile, then I read it's too rigid for glass, so had some confusion there.
I am trying to make sure I have the right floor materials down first before the tile, but I don't know what your abbreviations mean. (I have a 1/8" plywood and 1/2" wonderboard screwed down, but worried it is too flexible.) I am not sure if you will be back to answer, so I think I will start a new thread w/ my question, but if you are here again, could you spell out what you used for the completely clueless? Thanks!