Laying Tile over Wood Floor

6142 Views 13 Replies 5 Participants Last post by RMCarner, May 20, 2009

RMCarner

Discussion Starter · Apr 30, 2009

Hi,

I have gutted a kitchen and removed several generations of linoleum and am down to the original tongue and groove wood floor. Should I go ahead and install cement board first? If the answer to that question is yes, then would it be ok to use a subfloor grade of liquid nail instead of a thinset with the cement board?

Thanks.

Dick

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JazMan

· #2 · Apr 30, 2009

Dick,

Where did you get those ideas? All wrong! :yes:

If your "original" t&g floor is the subfloor, you can leave it, but you must install a plywood underlayment over it first and then the CBU or a membrane such as Ditra. If you go with the cement backer (CBU), it is installed into thinset mortar and immediately fastened and then taped per directions.

Jaz

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RMCarner

Discussion Starter · #3 · Apr 30, 2009

JazMan said:
Dick,

Where did you get those ideas? All wrong! :yes:

If your "original" t&g floor is the subfloor, you can leave it, but you must install a plywood underlayment over it first

Okay. Why do I need a plywood underlayment? Not challenging you, just questioning.. Second, what are you recommending - 3/4" or what? And what type. This will really raise the elevation of the floor more than I anticipated adding the plywood.

and then the CBU or a membrane such as Ditra. If you go with the cement backer (CBU), it is installed into thinset mortar and immediately fastened and then taped per directions.

Jaz

I bought Hardibacker board 1/4" from Lowes. I didn't know either about the membrane that is required.

Thanks.
Dick

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JazMan

· #4 · Apr 30, 2009 (Edited)

Dimensional lumber is too unstable to apply the Hardie or any CBU to directly. You should install min. 3/8" B/C underlayment grade or thicker, (I recommend 1/2" if the planks are in "like new" condition), the thicker the better of course.

Installing tile using this method will be lower than the old fashioned alternative. The old way you would install 1 1/4" or more of cement mortar, then the tiles. (Can be thinner if a small room like a bathroom) If you want all the floors to be the same level, install the same floor in all rooms. :thumbsup:

You don't need both a CBU and membrane. One or the other. Ditra is a better method, is only 1/8" installed and of course costs 2.5-3 times more. but easier to work with and no silica dust that can kill you in 70 years. (?) :whistling2:

Jaz

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RMCarner

Discussion Starter · #5 · Apr 30, 2009

JazMan said:
Dimensional lumber is too unstable to apply the Hardie or any CBU to directly. You should install min. 3/8" B/C underlayment grade or thicker, (I recommend 1/2" if the planks are in "like new" condition), the thicker the better of course.

I'm listening. I'll opt for 1/2"

You don't need both a CBU and membrane. One or the other. Ditra is a better method, is only 1/8" installed and of course costs 2.5-3 times more. but easier to work with and no silica dust that can kill you in 70 years. (?) :whistling2:Jaz

I hear that. The cement board is nasty stuff. Okay quick run down. 1. Install plywood. 2. Get Ditra install with thinset. 3. Tile.

Any particular pattern laying the plywood? Thanks a bunch.

Dick

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JazMan

· #6 · Apr 30, 2009

OK,

1. Fasten the old boards, replace bad ones.
2. Install new ply with long edge across the joists. Fasten only into the subfloor. Use screws that are about 1 1/4" long, no cheap drywall screws. NO glue under plywood.
3. Install Ditra with modified thinset mortar using a 5/16" V trowel. Follow directions, make the thinset a bit thinner than normal.
4. Set tiles using a good grade of UNmodified thinset, even if the tiles are porcelain or other hard to bond tiles. Try to find Ditra Set thinset near you.

Jaz

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Quadfam4

· #7 · Apr 30, 2009

Saw a guy on DIY ten grand in your hand tell the guy he had to glue the CBU before he screwed it into the plywood is that right?

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bdobs

· #8 · Apr 30, 2009

Quadfam4 said:
Saw a guy on DIY ten grand in your hand tell the guy he had to glue the CBU before he screwed it into the plywood is that right?

Thinset, not glue. The purpose of the thinset is to fill any voids. Any flex=bad.

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Quadfam4

· #9 · Apr 30, 2009

no it was glue. at first he just screwed down the CBU then the guy told him to take it up and use like liquid nails to glew it down and then screw it down. I am pretty darn sure it was glue not thinset came out of a caulking gun.

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JazMan

· #10 · Apr 30, 2009

ALL CBU's must be installed with either un modified or modified thinset (instructions tell you), under them. This thinset is NOT there to bond the CBU to the subfloor, but to fully support the sheets. The fasteners hold it down, the thinset hold it up, this way there is no movement.

Back in the '70's when "Wonderboard" first came out, it was suggested that the board be installed as you said. With a bead of construction adhesive around the perimeter, a big X corner-to corner and then "O"'s everywhere else. They learned within a few years the board was moving and many jobs had grout cracks. The current method has been the "law" ever since with great results if everything else is done right too. :thumbup:

There of course are still some people, even pros, that haven't gotten the news yet. And some of them will say they have never had any problems doing it the wrong way. I think they have, but just may not know it or the customers didn't complain. Hairline cracks are very difficult to see, and many people expect some small cracks in the grout, for some reason. :no:

Jaz

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bdobs

· #11 · Apr 30, 2009

I installed Travertine flooring and tub enclosure in my bathroom. Just to see what kind of quotes I would get from the "pros", I had about 5 estimates given to me by licensed "pros" I found in the yellow pages.

I had used Hardibacker before, and did my research on a bathroom install.

3 of the 5 said they would simply nail the Hardi down directly on subfloor, 4 of the 5 said I didnt need a vapor barier over the studs for the tub enclosure, and not a single asked about my deflecto rating or joist structure. Upon me asking, one guy leaned on one leg and said the floor seemed stout.

Glad I did it myself

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RMCarner

Discussion Starter · #12 · May 1, 2009

JazMan said:
OK,

1. Fasten the old boards, replace bad ones.
2. Install new ply with long edge across the joists. Fasten only into the subfloor. Use screws that are about 1 1/4" long, no cheap drywall screws. NO glue under plywood.
3. Install Ditra with modified thinset mortar using a 5/16" V trowel. Follow directions, make the thinset a bit thinner than normal.
4. Set tiles using a good grade of UNmodified thinset, even if the tiles are porcelain or other hard to bond tiles. Try to find Ditra Set thinset near you.
Jaz

All good. Thanks very much. I have a hard copy of what you said and will follow your directions. Thanks

Dick

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wahine

· #13 · May 20, 2009

ceramic tile over t&g flooring

my first question was on the black adhesive under the carpet i pulled up after water damage, how to get rid of it? I sanded it, but it will all not go away, i wanted to know if i could lay the tile on it and if it would be okay.

then i found out i have to put a plyboard or hardboard over the orig floor before the tile, doesn't that mean i need to remove all the baseboards and door trims, omg I think i'm getting myselft into something way bigger than i thought, the laying of the time is the easiest part.

i have all the tools, could wing the knowledge just need to know the steps in easy terms.

sandy

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RMCarner

Discussion Starter · #14 · May 20, 2009

wahine said:
my first question was on the black adhesive under the carpet i pulled up after water damage, how to get rid of it? I sanded it, but it will all not go away, i wanted to know if i could lay the tile on it and if it would be okay.

I relied on a 1500 watt heat gun to loosen the linoleum and tar paper from the tongue and groove floor. You don't need to apply much heat! In some places it all simply came off by force (big chisels, etc.) But, I did make sure to take it all off before laying down the plywood.

then i found out i have to put a plyboard or hardboard over the orig floor before the tile, doesn't that mean i need to remove all the baseboards and door trims, omg I think i'm getting myselft into something way bigger than i thought, the laying of the time is the easiest part.

In my opinion, no. The only think I got rid of was the quarter round that was up against the baseboard.

Dick

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