new tile floor - Contractor Talk - Professional Construction and Remodeling Forum

JamesNLA · 09-12-2007, 07:30 PM

ok..ok, I really have no business on this topic...but here I am.

Jury duty next week, so I have blocked off time to do an upstairs bathroom floor. My PITA wife has been bugging me for months to do this so here goes. Mind you I know just above nothing about setting tile!!

about 80-90 sq ft.
Second story floor
existing floor details:
2X12 12" OC 2nd floor framing
1X4 sub floor
1/2" partical sleeper
Lanoleum (sp) 12"X12" squares

My thoughts:
Remove sleeper throughout
backer board directly on top of sub floor
thin set and tile.

Tiles are 12" mos.

So I am looking to know if I am on the right path?

There was alot of water damage from getting out of the shower and either not drying off or just not caring and letting water all over the floor. 3 day fixing that little jem.......Thanks Kids...Daddy will fix it!

Anyhow, your direction is appreciated

reveivl · 09-12-2007, 08:33 PM

What does: 12" mos refer to?

James, back up one step, what is the span of the 2x12's? Likely the span isn't too great to support tile, but it's good to be sure at this point. 1x4 is not sufficient over the joists for tile, and backer board adds no strength, so you're gonna need some plywood in there. At least 1/2" screwed into the sub, not the joists. (While you're there, make sure the 1x4 is well attached to the joists.) Then unmodified thinset under the cbu (can be 1/4" on a floor) screwed down. Then you're ready to tile!

JamesNLA · 09-12-2007, 08:45 PM

Quote:

What does: 12" mos refer to?

mosaic squares (with the netting holding it all together)- 12"

The 2 X 12 floor joists are either 11 or 12" on center. You're saying the sub floor isn't sturdy enough to hold these tiles?

reveivl · 09-12-2007, 09:07 PM

There's two ways the floor has to be sturdy for tile: The joists must be rigid, so you need to know the span of them from support to support, not the space between them; and then the floor on top of the joists has to be sturdy between the joists, (so it can't deflect from joist to joist with traffic).

I wouldn't tile on that sub floor for any customer, and guarantee that it wouldn't fail. 1x is not a suitable substrate for tile, it does add support, but you need to add some ply. 1x material moves a lot with heat/cold and wet/dry and you need to isolate your tile from this movement.

Do you have transition height issues that you don't want to add the extra ply? I would suggest a membrane which would save you some height, but doesn't work well with the mosaic (small) tile you have chosen.

JamesNLA · 09-12-2007, 09:20 PM

Quote:

Do you have transition height issues that you don't want to add the extra ply?

no, I just don't want the extra work. Damn my wife for this. I knew this was gonna suck......sigh...

OK, the spam has to be atleast 13-15 ft, the bathroom is almost right in the middle of that span. There is carpet in the bed room so the transition by using 1/2" ply will set me up higher than I'd like to be, but I don't want to ever have to deal with this floor again.

So:
subfloor 1x4 (I will nail them all off again)

1/2" ply nailed off (I usually use liquid nails for this sort of thing as well as
nailing/screwing)

than backer board (you called it "CBU") dunno what that is

thin set and tile

Will that keep her quiet on this??

Floordude · 09-12-2007, 10:27 PM

Quote:

Originally Posted by JamesNLA

no, I just don't want the extra work. Damn my wife for this. I knew this was gonna suck......sigh...

OK, the spam has to be atleast 13-15 ft, the bathroom is almost right in the middle of that span. There is carpet in the bed room so the transition by using 1/2" ply will set me up higher than I'd like to be, but I don't want to ever have to deal with this floor again.

So:
subfloor 1x4 (I will nail them all off again)

1/2" ply nailed off (I usually use liquid nails for this sort of thing as well as
nailing/screwing)

than backer board (you called it "CBU") dunno what that is

thin set and tile

Will that keep her quiet on this??

CBU is Cement Board Underlayment.

Be sure you comb out thinset and lay the CBU into it, and screw or ringshank nail it off as recommended.

JazMan · 09-12-2007, 10:40 PM

Hi James,

You've pretty much got it.

Only exception, you should NOT use liquid nails or any adhesive from a tube under any underlayment.....ever. It actually makes things worse, it creates hollow spot....lots of them. Just use good quality rust resistant screws that just penetrates the subfloor. About 1 1/4" or so. NO drywall screws. Buy underlayment ext. grade plywood that is C/C or B/C and plugged. Do NOT buy sheathing grade C/D or C/D X plywood. Many people that buy materials from the big box stores are tempted to buy the cheap stuff instead of underlayment. Sheathing is NOT for floors.

The Cementitious Backer Unit (CBU) is of course set into freshly spread thinset mortar with the recommended trowel. Usually 1/4"x1/4" square notch, and fastened right away using either the special CBU screws or galv. roofing nails. Most manufacturers recommend modified thinset under the CBU and always modified to set the tiles. You have to use modified with porcelain tiles anyway. You can get away with unmodified under the board, but then you'd have to buy 2 types. Be sure to tape and thinset all seams with the special fiberglass mesh. Follow manufacturers directions.

Jaz

reveivl · 09-12-2007, 10:50 PM

You're certainly good to go on a 13' span. Don't glue the plywood down (there, saved you some work!) just nail or screw it to the subfloor. Try to avoid nailing the ply into the joists, but nail/screw it well into the 1x4. As floordude says, you want to put thinset under the cbu (backer board), this removes any chance of there being voids under the cbu, and adds one more layer between the tile and the unstable wood below. Then use a modified thinset to set your tile.

Don't know if I want to share this with you, as I imagine it wasn't you who picked the tile

, but, those mosaic sheets can be a bit of a bear to work with. The sheets themselves are often not perfectly square; don't put down too large of an area of thinset until you get the hang of it. You need to press the sheets into the thinset, but don't work them too hard or you'll have thinset coming up between the mosaics, and it's a b!tch (ie. time consuming) to get it out of there. Any that does come up has to be removed otherwise you'll see it when you grout.

If you're using white tile/white grout, you can also get white thinset, which helps a little for the inevitable 'oops'.

JamesNLA · 09-13-2007, 12:22 PM

Ok, I got it!! Thanks for all the replies, it is appreciated. Any of you boys need plumbing help, don't hesitate!

Oh, one more thing the threshold from carpet to tile keeping in mind the flooring heights, which ones (if any) should I put in.

Thanks!

JazMan · 09-13-2007, 07:45 PM

Use a marble threshold. The width should be the thickness of the wall, usually 4 1/2". Set it so it is about 1/4" higher than the tile in the bath. Might need to add a shoe molding in the hallway side?

Jaz

MattCoops · 09-13-2007, 07:54 PM

You can always get a wood threshold cut with a custom reduction.
And I don't think it HAS to be the width of the walls.
I think the thresholds thicker than 3" looks too much. Especially with a smaller mosaic.

reveivl · 09-13-2007, 07:59 PM

Marble is certainly gorgeous, another option is to rip the appropriate shape piece of wood on the table saw so that the tile/threshold transition is under the door (invisible from the bathroom when the door is shut), varnish it, and presto, your wife is happy and on her way back to the honey-do jar.

Edit: Matt types faster than me.

JamesNLA · 09-15-2007, 07:11 PM

OK, demo is done, screwed off ALL the sub floor and laid down new 1/2" ply. I now get why that is important!!
I was just informed that I will not be putting a threshold in. I was told to simply make it work, in the transition from the carpet to the new tile. The top of the carpet and the tile will be almost flush. I want to dive the tile down or something so there is not an edge to bite little feet dragging across it, or stubbing a toe (namley mine). Any ideas?