Two Bathroom Remodel Questions

[buckeye95]

All,

I am the middle of a bath remodel and have a couple questions I was hoping to get some advice on:

1.) My wife really wants me to put down 12"x12" tile after having lived with linoleum so long. I asked a friend who had done this before, and he was concerned the subfloor would not be solid enough to prevent bowing and the accompanying cracking of grout. The room is 5' x 8' with a 5/8 or 3/4" OSB subfloor mounted on 2x8's with 18" centers. I was planning on installing 1/2" duroock on top of this before tiling. Does this sound like it will be rigid enough to avoid flexing, and the accompanying breaking of grout ? Unfortunately, the bathroom is on the second floor, so I am unable to go underneath and beef up the joists with extra support.

2.) I have torn out the old steel tub and will be replacing it with a new plastic tub (not sure if it's acrylic or what, but it's made a Sterling a division of Kohler). The instructions seem to imply that a mortar bed is optional, and is only really required if the subfloor is uneven. However, when I look at the bottom of it, it really rests on about six short rods right on the floor. Not to far up from the bottom of these "rods" is a large base of cross-hatched plastic (I assume to grip the mortar when a mortar base is used). If the subfloor is level, is it OK to not use the mortar bed ? Will the tub shift and bow too much ? I'm just concerned that the weight of the tub + water + occupant might be too much to rest solely on those six supports.

Any advice would be appreciated.

Regards,

Pete
Buckeye95

[onedash]

Well the shower stall we have in our bathroom was not put in a bed of anything (if it was it wasn't done right) because it flexes everywhere you step. There are more things wrong with this place than any I have ever rented. At least I learned a lot of what not to do someday when I buy....No idea if it wasn't supposed to need it. Looks like its been there since the house was built in the 70's and needs replacing but I doubt they will..

[Popeye]

I tiled two bathrooms year before last with 12" tile. used 1/4" durock. I don't see any problems with what you have.
One of my tubs had a glassed in runner that called for shimming the tub up level. did that, so far it's been real solid.
The other had no support and had to be mortared in. The mortar wasn't hard to do but it was a two person job. That one is a garden tub in the master bath. Feels real solid, kind of wish I'd done that with the other one. My house is on a crawl space BTW. Ask a plumber for the type mortar. I happened to catch the Quickcrete guy at Lowes to direct me to the correct type. Pat

[Slik Geek]

If the subfloor is level, is it OK to not use the mortar bed ? Will the tub shift and bow too much ?

I've found it annoying stepping into tubs that don't have the mortar bed. It doesn't make one feel secure when the "floor" beneath sinks with each step. The mortar bed isn't structurally required, but for a "quality" feel, I would recommend you include it.

[Cheeky]

i had a remodel gone bad, and then let the contractor go, and decided to tear everything out he and his crew did.

2 problems arose when he used 1/2" rock:

the transition from the wood floor into the hallway was so extreme, that i would have had to have a special marble threshold made.

2nd, the baseboard heaters would have had to be adjusted, because the covers didn't fit (the raised floor prevented the covers from going back on)

i used an underlayment made by Schluter (DITRA), and it solved the problems.
http://www.schluter.com/english/prod...601-index.html

i'm not saying not to use rock, but just think of any potential problems which might arise with a loss of 3/4 to an 1" with the rock, mortar and tile.

[PALefty]

All,

I am the middle of a bath remodel and have a couple questions I was hoping to get some advice on:

1.) My wife really wants me to put down 12"x12" tile after having lived with linoleum so long. I asked a friend who had done this before, and he was concerned the subfloor would not be solid enough to prevent bowing and the accompanying cracking of grout. The room is 5' x 8' with a 5/8 or 3/4" OSB subfloor mounted on 2x8's with 18" centers. I was planning on installing 1/2" duroock on top of this before tiling. Does this sound like it will be rigid enough to avoid flexing, and the accompanying breaking of grout ? Unfortunately, the bathroom is on the second floor, so I am unable to go underneath and beef up the joists with extra support.

There is a calculator to measure Deflecto over on JohnBridge dot com (great tiling site) which should help. You put in the above info and it should tell you if it is enough. Also, I am no tiling expert.. but from what I have read, durock/cement board/etc does not provide any structural support and will not count in your calculations. The answer would be more plywood or more joists underneath if deflection is a problem.

[thestinker]

The floor you have should be fine. I would put the bed in under the shower...it will help make everything more stable. Kind of like a good foundation.

RS

[jAngiel]

It was optional on the one that I installed in our addition and I hooked it up and filled it halfway with water and stepped in. It gave a litte too much for my liking so I yanked it out and put in a mortar bed. It doesn't take much and it makes if feel a lot more sturdy.

All I had to do for the mortar bed was mix it up and dump it on the floor where the tub went and set the tub in and squish it down. When it dried I had one solid tub.

[bhanna1]

re-did mine

When I re-did my bath...also on 2nd. floor...floor was 3/4 in ply, nailed to joists. I screwed the ply down tight, then added 1/4 ply for tile subflooring, with all joints much offset, used construction glue and screwed the sandwich to the joists every 4" throughout, then set the tile in thinset. That was 10 years ago, there hasn't been a sign of a crack since, there is no flexing or creaking...and this is the only floor in the house that doesn't creak.