Tile over wood or cement?

[navychop]

We have a tub whose edge is 1.5" above an attached shelf. The shelf is about 4" wide/40" long and we normally step over it, but sometimes sit there. Since we added a shower head over the tub, we are putting up a swing open shower door over this shelf. The door will be attached to the wall at one end and freestanding/open at the other.

The wall is also about 4" wide and centers over the shelf, so the shower door will hang over the shelf, not the tub. This means water hitting the door will drain down onto the shelf and the floor. So we plan to build up the shelf to just over the tub. The shower door has a rubber strip at the bottom for a seal. We will put tile down for this strip to seal over, and drain the water back into the tub. The problem is, we must build up the shelf to "fill in" the 1.5".

We considered backer board, but this really wouldn't be strong enough for a spot that might be stepped or sat on. We also considered stacking two 3/4" marble thresholds, but that involves cutting a tricky angle at one end, and concerns over the mastic adhering to the marble. We're down to putting in a roughly 2" wide, 1.5" tall, 40" long piece of wood (treated or not) or anchor cement. Then laying the tile over that.

Any input on which would be better, or some other idea?

Thank you.

 

[Van]

Marble would be your best bet for a rigid foundation, wood will flex and if you step on that ledge and the wood flexes then the groute will crack. You can rough the surface of the marble up with a heavy grit sand paper or a go over the surface with an electric or air grinder. Check with a countertop or marble supplier in your area, they will have various thickness stone and you would be able to get discard pieces on the cheap, heck you might even find a piece that looks to good to cover up.

Adding some thought to this, if the ledge currently has a rigid support to it then you could go with the wood but you would want to go with pressure treated wood so that it will last longer with moisture if it ever becomes a problem

 

[navychop]

The shelf is corian or similar and very firm. We went to the tile supplier we used for the rest of the bathroom- no stock of any sort over 3/4". Most marble thresh hold stock ends at 36". We could get 40" but would need to do 2 angled cuts at one end. Not sure how to do that without the proper equipment. My tile cutter would not work (score & snap) & I don't recall seeing a marble blade for my chop or circular saw.

So using the anchor cement I have doesn't appeal, eh?

Thanks for the continuing help.

 

[Van]

I would try a sample of the anchor cement on something sturdy with some tile sample and see how it goes, it never hurts to try.

 

[navychop]

Well, now you've given me ideas. I'm now thinking about getting two 36" long, 3/4" thick marble thresh holds, 2"-3" wide, and gluing them together and to the base with glue-from-god. Then roughing the top and side for mastic/tile. The 3"-4" bit at the end with a couple of angles is next to the faucets and maybe I can fill that with anchor cement. Tile, grout, hang door.

The tile will be bullnose baseboard tile (wall tile, not floor tile). But since it will be only about 3" wide, I doubt there's much worry about people stepping on it and breaking it. MUCH more likely to step over it.

 

[BobMurdoch]

Stay away from wood whenever you can when dealing with hard tile. Temperature and Humidity fluctuations will cause the wood to expand and contract, increasing the likelihood of cracking. Flexing will do it as well as someone else mentioned.....

 

[nsaspook]

Well, now you've given me ideas. I'm now thinking about getting two 36" long, 3/4" thick marble thresh holds, 2"-3" wide, and gluing them together and to the base with glue-from-god. Then roughing the top and side for mastic/tile. The 3"-4" bit at the end with a couple of angles is next to the faucets and maybe I can fill that with anchor cement. Tile, grout, hang door.

The tile will be bullnose baseboard tile (wall tile, not floor tile). But since it will be only about 3" wide, I doubt there's much worry about people stepping on it and breaking it. MUCH more likely to step over it.

Check out this site. John Bridge Ceramic Tile Forums - powered by vBulletin

 

[navychop]

Stay away from wood whenever you can when dealing with hard tile. Temperature and Humidity fluctuations will cause the wood to expand and contract, increasing the likelihood of cracking. Flexing will do it as well as someone else mentioned.....

Yet kitchen tile goes over wood subfloors, doesn't it? Different tile?

And thanks for the link- I'll look it over.

 

[Van]

Kitchens tend to get less moisture aside from the occasional spill or water line break. Bathrooms however have flushing toilets, sink usage, showers and baths several times a day not to mention shaving and brushing teeth ect ect.

 

[Paul Wozniak]

Van is correct on this one. Use backer board designed for tile installation, you'll be happier in the long run. Found this out the hard way. Van, good to see your health is improving. My blood pressure is now 120/70. Better living thru chemistry I guess.

 

[Van]

Change of diet has made a big diference, if your a pub member you can find my diet thread in the pub members forum detailing the last month and half as well as posts from other members who are working towards their own weight loss goals.

Not a pub member?? Well its easy and incredibly cheap and for just $20 a year you get access to pub member only sections and you'll see less advertising than you do now and trust me the diference is night and day. Not sure how to become a pub member? Well all you have to do is click on the link at the top of the page or you can ask any staff member or even the infamous owner / super model in training Scott and you will soon be on your way to becoming one of the exalted pub members.

 

[navychop]

Van is correct on this one. Use backer board designed for tile installation, you'll be happier in the long run. Found this out the hard way. Van, good to see your health is improving. My blood pressure is now 120/70. Better living thru chemistry I guess.

Yes, I'm leaning toward this, but we're talking about roughly 40" strips that are only 2"-3" wide, and layering them up to 1.5" thickness. Will this be stable and sturdy? I'm concerned that it be capable of holding up and not crumbling if someone sits on it.

Also, which backer board? Cement, as in Durock or Wonderboard? I know enough not to use greenboard/greenrock. Then there's densshield, fiberock, rhinoboard and who knows what else?

I'd be dead now if it weren't for chemistry. And seat belts.

 

[Van]

Good questions, I dont know enough about the board types but moisture resistance and tensile strength are both important specialy in your application. If you can sit on that sill now and it doesnt sag then thats a plus in your favour but you need something thats going to provide definite rigidity.

 

[Paul Wozniak]

You're biggest problem is the width 40"(?). As long as you have a support stud about the middle, you should be able to use a piece of marine plywood covered with durock or wonderboard, and then your tile. Like I said, support in the center will prevent stress at the middle of the board and prevent cracking your grout and tile. I know it's a lot of work, but it's your home and it deserves the best.

 

[navychop]

It's built like a brick outhouse. No flex at all. It's the top of a very short 2x4 studwall. The 40" long doesn't bother me, it's the 2 to 3 inches wide that concern me. And layering a "sandwich" of backer board to build up to 1.5". Wonderboard comes in 1/4" & 1/2" thicknesses, so we're talking at least 3 layers of board, glued together and to the base, and then having the tile applied.

Once made, would it crumble if someone sat on it? Would it adhere to what appears to be corian?

Looks like I may find out, if a better idea doesn't come along. I really need to do something this weekend.

Thanks to all for your help, and please feel free to comment on if it sounds like a good idea to layer wonderboard and tile it over.

 

[navychop]

Based on advice from 2 guys at the hardware store, I went with hardibacker, for strength. First layer poly glued to roughened corian and screwed in. Took 4 layers. Tile tomorrow night, then grout the next, and can get wet 2 days later.

 

[Paul Wozniak]

Let us know how it works out. Sounds like a solid plan.

 

[navychop]

Well, first the good news:
It worked fine. The hardibacker went together and is solid. The tile went over it just fine, with a slight slope into the tub. Door hangs straight and rubber scraper at the bottom touches the tile all the way across. Very little water splashes beyond the door.

Now the not-so-good news:
The tub has 5 openings on the top, which we neglected to consider: Faucet, two knobs, hand sprayer and hand sprayer selector. They all leak water during a shower, onto the subfloor and ceiling below, and thru the new wall onto the bathroom floor. First run with caulk has sealed some of them. Might need to remove and seal the area that has the hand sprayer.

 

[TheForce]

Don't most communities require tile over hardi board as a regulated building code? It is here.

 

[Van]

Im surprised that the tub didnt come with any kind of rubber seals or the hardware didnt, I remember that when I replaced the faucets in my grandmothers kitchen and bathroom that there were gaskets that came with the faucets to seal them and prevent water leaking.