Bathroom floor question - Contractor Talk - Professional Construction and Remodeling Forum

Eric K · 01-16-2007, 08:47 PM

I ran into a bit of an issue with the floor. Guys where doing the demo and went after the floor and seen it was like a cement poured floor on the 2nd floor of this 1930's home. My question is can I thinset over the tile that is there? It is 1"x1" squares in a 5'x8' room. We will be installing 12"x12" carrara marble on the floor. It is also getting a WarmlyYours radiant floor heat. Is this acceptable to do? If so, is there any certain precautions I need to know about. I've never laid tile over an existing floor. I always tear out whats there and use cement board, but Ive never run into this before.

Thanks

MattCoops · 01-16-2007, 09:12 PM

The flooring is a "mud job". It's a mix of sand and portland cement.
Demo that stuff. It'll wear you out a little, grab some homeless people you see on side of road and ask them if they'd like to make a couple bucks.
I've seen people rent jackhammers. You could use a cold chisel on end of hammer drill.
But really, all you need is a sledge hammer, a ripper hammer, flatbar, some buckets, and aggression

Smash the hell out of the tile in a square pattern, like a 3 foot square. Use grout lines as a guide, smash right on those lines. Then hammer the forks of the ripper hammer down into the metal lathe underneath
and keep hitting in same square line as you smashed to cut through lathe. Now pry underneath with flatbar and lift up large pieces at a time. Carry them down to truck. Continue. Don't cuss too loud.
then you can use flatbar for small areas. Throw that crap in buckets.
Sweep it all up. No dust or tile bits. Homeowners like to walk in after a demo and cut their feet. Sweep or get sued.

Then go home and have a beer.

So you want to lay tile!

MattCoops · 01-16-2007, 09:27 PM

TCA says you can set tile on tile
so long as "existing installatio must be sound, well-bonded, and without structural cracks."
- TR712-05 of TCA handbook

I've never done radiant heat over tile
done a couple over wood subfloors
never heard of that company. we used suntouch
just make sure floor joist aren't spaced more than 19" on center

and ask Bud Cline or RD about deflection. It gives me a headache, too mathmatical. Just use logic.

what we do, is after we lay heating system (and test it to see if it works) we mix an SLC by Custom and trowel that down flat. (make sure you shut off heat and it cools prior) this gives a smooth level surface. Then you just thinset and tile over all that. I suggest to preseal marble before grouting. Wait a day to grout. Clean up. Come back 3 days later to seal it. Use penetrating sealer for stone tile

good luck

Eric K · 01-17-2007, 08:10 AM

Matt,

Thank you for the suggestions. I have yet to see the floor. I am going there today to assess it. From what my lead guy told me the floor is solid with no movement at all. I'll keep you posted on what happens with this one. Well got to go to work...

J&J Home Imp. · 01-17-2007, 10:27 PM

I am always leary of installing over exsisting. Then my job is only as good as the guy before me. I would rip it all out if i were you.

troubleseeker · 01-17-2007, 10:32 PM

If there are no cracking problems with the existing, I don't see why you should spend time and money to remove it.If you are concerned, talk to your tile supplier about using an isolation membrane under the new tile. We see these pretty often in old houses. They are at least 2, and often 3 inches thick, and are seldom unsound, unless the floor has moved due to termite damage or rot. And be prepared, they are not a picnic to remove, as they usually contain wire of some sort, chicken wire, hardware cloth, or plaster lath.

As for MAttCoops idea about just smashing and beating the hell out of it, see if he wants to chip in to cover the cost of repairing the first floor ceilings.

No experience with radiant floor.

J&J Home Imp. · 01-17-2007, 10:41 PM

I have torn out quite a few mud bed floors and showers and once you get it going it goes pretty good. I have a Bosch rotary hammer that I use like a little jack hammer and go to town. 2 guys with a rotary hammer and some hand tools should be able to have a 5x8 tore out in about 4hrs.

Eric K · 01-17-2007, 11:14 PM

My concerns with tearing it out is that is is down so good, I am afraid of causing damage to the ceiling below. All the existing walls and ceiling are a very old and unique texture on the plaster. If there is any damage it would be near impossible to patch it perfect, then to match the paint on the rest of the ceilings.

hurricane hogan · 01-18-2007, 02:49 AM

Just went through one similar. The problem sometimes is the added height-if you go over the old stuff causing you to have to cut into mouldings - doors, adjacent floor heights etc With the new products on the market you can be pretty sure of going safely over existing if the existing floor isn't lose or showing cracks. Go to custom's web site, or mapei or whoever, with the trowel on antifracture membranes and fabrics available it's easier than used to be. Read their info about red guard and thier fabric, forget the name right now. Is that heat a mat or free wire? Mat is easier over concrete surfaces, Use a super modified thinset for the mat and for the tile (customs flexibond for example.) This bonds the mat better but also allows for some flex from the heat expansion /contraction. If it is free wire I now refuse to do it unless I pour self levelling over it first. Saves a lot of grief. Also, you should see this added material (self levelling cement) as another small profit area for yourself. I always remind my guys that we are in sales, believe it or not.
I'm not pushing the custom line over anyother line, I just use thier products as they are familair to me.
Also, sometimes taking out an old floor just isn't as much work as the worrying you might do afterwards for not taking it out. ?
I'm sure that claered things up for you - Ha.
Well, it's bed time for an old guy.....

J87513 · 01-25-2007, 02:58 PM

just do a dirt floor, I did it in my bathroom and it is awesome.

MattCoops · 01-26-2007, 10:38 PM

Pretty much any bath remodel we do on houses built prior 1980 have mud floors under tile.
We haven't had any ceiling problems by removing the existing floor.
If you're that neurotic, set a tarp in the room below.

Craig · 01-27-2007, 01:16 PM

I had this problem in my own bathroom remodel. Used an old circular saw with a masonry blade set to the depth of the mud bed. Made cuts in a 1' grid pattern and then removed the tile and mud bed in pieces. Worked pretty well and avoided too much hammering.

MattCoops · 01-28-2007, 10:04 PM

how many times did you change those expensive ass blades?

Ted W · 01-29-2007, 01:49 AM

I run into a lot of those bathroom floors in the old buildings I work in. After I remove the thick-set (as it's refered to in my area) with a rotary hammer and elbow grease, I build it back up with cdx plywood and a final layer of cement board. Just be sure to build it up the proper level so the tile ends up flush with the existing floor.

turner flooring · 02-04-2007, 03:24 PM

as long as you use An epoxy primer onto the other tile,and let it dry thoroughly, you should also use the best thinset such as versabond or any product with a latex additive.

turner flooring · 02-05-2007, 10:42 PM

You hit the nail on the head. No doubt..
Everything you said is right on, sucks installing floors..
Some days i'd just rather quit then go thru the hell of what we have to do..

MattCoops · 02-05-2007, 11:06 PM

I love installing floors

I always tell the customer when were finished
that now they can walk all over us

Each floor joist we brace, each backerboard we slap down, each screw we drive home, all the mud we trowel, each tile we set, it holds a piece of us, and it wall last longer than we're here on this earth.

Period.

PrecisionFloors · 02-05-2007, 11:20 PM

Quote:

Originally Posted by turner flooring

You hit the nail on the head. No doubt..
Everything you said is right on, sucks installing floors..
Some days i'd just rather quit then go thru the hell of what we have to do..

Quote:

Originally Posted by MattCoops

I love installing floors

I always tell the customer when were finished
that now they can walk all over us

Each floor joist we brace, each backerboard we slap down, each screw we drive home, all the mud we trowel, each tile we set, it holds a piece of us, and it wall last longer than we're here on this earth.

Period.

The difference between bidding em right and making the profit margin you need and doing it for cheap to be "competitive" right there in between the lines.

turner flooring · 02-18-2007, 06:17 PM

Quote:

Originally Posted by MattCoops

The flooring is a "mud job". It's a mix of sand and portland cement.
Demo that stuff. It'll wear you out a little, grab some homeless people you see on side of road and ask them if they'd like to make a couple bucks.
I've seen people rent jackhammers. You could use a cold chisel on end of hammer drill.
But really, all you need is a sledge hammer, a ripper hammer, flatbar, some buckets, and aggression

Smash the hell out of the tile in a square pattern, like a 3 foot square. Use grout lines as a guide, smash right on those lines. Then hammer the forks of the ripper hammer down into the metal lathe underneath
and keep hitting in same square line as you smashed to cut through lathe. Now pry underneath with flatbar and lift up large pieces at a time. Carry them down to truck. Continue. Don't cuss too loud.
then you can use flatbar for small areas. Throw that crap in buckets.
Sweep it all up. No dust or tile bits. Homeowners like to walk in after a demo and cut their feet. Sweep or get sued.

Then go home and have a beer.

So you want to lay tile!

This is what I was talking about sometimes it's just a long hard day. Been through so many of these days. That's what I was talking about.
This is the part of flooring that requires no skill. Just basic labor. I love the showing off side where, it requires skill. But when it''s all taking trash out, I prefer to get my crew with no experience on this and look forward to the next job that has some defining touches
needed. Pattern jobs with materials like Forbo,10 or more colors,crazy circles and radius with squares, 10 different weld colors to distinquish the accents of all materials. That's what i love about flooring. Never will love all aspects of the flooring installation. Cleaning out rooms full of painters dust is hard to LOVE ANYMORE. Overall it's a business that can grow on you. But you hit the nail on the head with exactly all the details of that job and what it needed.