Tile on concrete [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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spark chaser
08-03-2001, 08:22 AM
I have read as many posts about tile on concrete as I can find. I have a basic question.

On a 1 year old slab, what do I have to do to install ceramic tile on the concrete? The slab is smooth and level (within under 1/4 inch across 8 feet), no cracks in the area at this time. Going to try to tile 60 square feet.

I bought several books, and they all instruct me to lay down a plastic (?) membrane before I lay the tile. To me, this would cause the tile to not be firmly bonded to the floor, and would cause the thinset and grout to crack.

I know if the slab cracks under the tile, any tile bonded to the concrete will also crack.

I make my living with dykes, strippers and crimpers, this floor laying is new to me. If it were not my floor, I would tell the customer to call a pro.

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John Bridge
08-03-2001, 01:16 PM
Hi Sparky,

I don't know which books you read, but it is not necessary to lay down a crack isolation membrane if the slab is in good shape. It would not be a bad idea, though.

I think if I were you, I would just use a good polymer modified thin set and let it go at that. 60 square feet is really not much of a gamble.

What part of the world do you live in?

Bud Cline
08-03-2001, 03:00 PM
OK here I go....."fools rush in where wise men fear to tread".

Given the perameters established within your statement above chaser ole boy, I have two questions: 1.) What the hell is a "crimper"? (and) 2.) Am I going to be really sorry I asked after I find out?

John Bridge
08-03-2001, 04:01 PM

Sparks (electrician), dykes (electrical pliars/side cutters), strippers (not the kind you like), crimpers (as in crimping thingies on wires?)

Bud Cline
08-03-2001, 04:25 PM
"SHEESCH" that's a relief, I thought you were going to have to start yet another forum and hurry up about it.

OK kids you can come back in now! LL,it wasn't what we thought! LL? LL? "LAURA LEE"?

Well crap I gotta go now!

Rob Z
08-03-2001, 06:09 PM
thank goodness, we got an electrician on the board now!(side question, sparky: ever had a non tradesman get miffed when over hearing you talking about dykes?)

We may call on you when we have an electrical question.

Just to add to what John said...drip some water on the slab to see if it absorbs or beads. Also, if you would like some extra insurance on the slab, use Schluter Ditra as a crack isolation membrane and to equalize any vopr pressure from coming up through the slab. I think Schluter is selling Ditra in small packages, so you may not need to buy more than you need.

Let us know if you're interested in that (or another product) and we'll talk you through it.


08-03-2001, 06:30 PM
Boy, I just stuck my nose over here for a minute, dykes and strippers? I thought this was a family forum! I'm going back to the other side where there's beer, moonshine, wine, illegal aliens in Canada, boats and other wholesome stuff.

spark chaser
08-03-2001, 07:51 PM
John got it right, seems every trade has its own lingo.

Rob, nope - never had anyone get in a snit over "dykes", I have cut phone wires with them while the owner was talking, she thought she should get excited about it, so I went and pulled power on the main panel. It made her forget all about the phone.

Back to the slab. Monolithic slab with rebar in footings and fiberglass added to concrete. Slab portion about 5 inches thick. Due to location (very corner of bldg.)and several piers outside of area to be tiled, I do not expect a crack problem in this area. Location : middle Ga.

It is a bathroom floor.

When I drip water on the slab, it doesn't really bead, just a damp spot. Boards left on the concrete for several days do not leave a damp area when removed.

I would prefer to apply the tile directly to the slab, but I want the floor to be serviceable without becoming troublesome.

Thanks all for the replies.

Rob Z
08-03-2001, 08:06 PM

I had someone get testy hearing dykes in conversation before. And many don't like "male, female" for fittings, either.

It's good that your water soaks into the slab (the thinset will bond).


Bud Cline
08-03-2001, 08:28 PM
OK Sparky do you know what a pidgeon pecker is?

Rob Z
08-03-2001, 08:33 PM
Is that a "tool"?

spark chaser
08-03-2001, 08:52 PM
Rob, I believe dyke is short for "diagonal cutter". You just have to use a discriptive term, or your partner ends up handing you the wrong "thingie". And, if you tell someone to "just dyke it off" there is never any question about what to do.

If I run into resistence over commonly used names (as in male/female) I just mention I did not make it up, it is common in the industry.

I would think more folks would question "butt connector" than anything else, never had a problem with that either.

When using the Ditra, how do you maintain a level surface? Do you have to use a roller to lay it down like a laminate?

Is it applied and left for several days to allow the thinset to cure, then more thinset and tile?

The stuff looks like it could be difficult for a novice to use.

spark chaser
08-03-2001, 08:56 PM

Don't think so.

Not a welders chipping hammer by any chance, is it?

Rob Z
08-03-2001, 09:03 PM
The Ditra is a breeze to put down. Trowel out thinset and use a flat tool (trowel, float, 2x4) to flatten it into the thinset. Schluter says you can get right on it and set tile.

Yeah, the male/female thing...I always say when someone expresses squeamishness...can you think of something more descriptive?

I HAD always wondered where the term dykes came from.

Check out Schluter's website http://www.schluter.com.


Bud Cline
08-03-2001, 09:25 PM
Pidgeon peckers are used in the communication industry. They are tiny little connectors that are crimped onto wires being spliced. All I have ever seen are white little ??? looking things about the size of a pidgeons ??? well I don't know let's ask Art, he knows about these things, he must.

Hey Rob? "Conduit hickey"?

DITRA would run the cost up probably for no good reason in this case. I side witg John, go for it.

spark chaser
08-03-2001, 09:36 PM

I have always referred to those as "beanie buttons". Come in a bag of 1000 each? I can't get the white ones anymore, only the yellow. The white ones are slightly bigger than the yellow, and easily handle 2 18 ga wires. I think the brand name on the white is Dophin, not sure.

The first time I used them, I really questioned their ability to make a good connection without stripping first.

I must have checked 50 installs with my meter before I would trust them.

Rob Z
08-03-2001, 09:42 PM

Whatsa conduit hickey?

No one like my pun for pidgeon pecker, huh?

08-04-2001, 05:38 AM
No, I wouldn't know about anything that large!

And don't tell the wife there is.

I gotta go clean the pidgeon doo off the statue.


Bud Cline
08-04-2001, 07:48 AM
Boy, I'm glad there's no plumbers here right now, the conversation and terms could really go down the drain fast.

John Bridge
08-04-2001, 02:01 PM
Actually, when I described dykes, I was thinking about "Klines."

Bud Cline
08-04-2001, 03:03 PM
Now see John; there you go. I was going to leave it alone from that point, but now you have forced me into talking about plumber stuff ie. nipples, male adapters, female adapters, petcocks, we should really be in the Mud Box with this you know!

spark chaser
08-05-2001, 07:53 AM
Went to get stuff today. What is the difference between mortar and thin-set mortar?

The store had no latex modified thin set mortar, just "thin-set mortar", or "latex modified mortar".

I assume if it doesen't say "thin-set" it isn't.

John Bridge
08-05-2001, 08:08 AM
Generally, everything that contains cement and sand is mortar, aka "mud."

The thin set mortars are usually kept where the tile is in places like home depot, while the regular cement products are elswhere.

Thin set mortar will spell out on the bag what it's used for. Latex modified dry set mortar, polymer fortified thin set mortar are pretty much the same thing.

Brand names include Custom, TEC, Mapei, Laticrete, whatever Art sells, etc.

Bud Cline
08-05-2001, 08:19 AM

Don't buy the $5/50# bag stuff please. Pay a little more and enjoy the results for many more years.

spark chaser
08-05-2001, 06:24 PM
After reading of other's experiences, I decided a little schooling was in order.

Bought some Mapei Ultra-Flex 2. Got a piece of 3/4 plywood, and did a practice run. Will end up laying 12 tiles or so, let it sit for a few days and grout.

Is the selected mortar OK ?

Have already seen I am a bit messy, but cleaned the erant mortar with a wet rag, trying not to drip water between the tiles.

If all goes well with the grout, will try to do the floor next weekend.

Rob Z
08-05-2001, 06:59 PM
Mapei makes good products. I think the one you have is a "mid grade". It should be fine.

Rob Z

08-07-2001, 09:59 PM
Buy yourself a bucket of latex applied membrane such as Bonsal WP-6000 or similar. Roll it over the floor two coats. Then set your tile to it. extra cost for 60 sq ft probably about 40.00

Rob Z
08-08-2001, 05:45 AM

Birdog is recommending this for crack isolation purposes. If you want to go in that direction, we can tell you about the various products that are out there.


spark chaser
08-12-2001, 08:43 PM
Put down 21 tiles today, averaged about 6 tiles per hour.
It appears I can set maybe 30 tiles (12 X 12) with a 50 pound bag of mortar. That sounds like an excessive amount of thinset to me, but I am not bedding the tiles very deep, maybe an eighth of an inch or so.

I have been trying to set all the full tiles first, then go about cutting and fitting. This sound OK ?

Will a score and snap cutter cut as small as 1/4 inch off a tile, or is that a job for a wet saw ?

Thanks for all the answers and encouragement.

Bud Cline
08-12-2001, 09:08 PM
Sumpin's wrong here. You should be getting around 75 square feet (tiles) per 50 pound bag. How thick are you installing your bed and why and with what trowel?

If you have door jambs involved then they should be set as you go or you may not get those tiles to tuck into place.

The 1/4" cut on a score-n-pop is possible but really depends on the tile. I probably couldn't do it but some people can, the tool has something to do with it to. Why do you need only a 1/4"? Can't you fudge some things somewhere and eliminate the 1/4" completely?

Rob Z
08-12-2001, 09:22 PM

I have a really top quality snap cutter, and I can't get that small of a piece of the tile. And I don't like to use the biters on big, heavy tile. I like the wet saw.

You could be getting 30 feet per bag if you are using a 1/2" x 1/2" notch trowel. How's your coverage ? Are you checking tiles periodically?

spark chaser
08-12-2001, 10:10 PM
Laying the mud out with the flat side of the trowel, about 3 sq ft at a time, then combing with the other side (3/8, I think. Size recommended on bag).

I messed up this morning, had a 2" space I wanted to cover, so moved my lines supposedly 1 3/4". Problem was, coffee had not taken effect yet, and 2" minus 1/4" equaled 2". So now I am jammed up against a shower base, my solution was to try to cut 1/4" off 3 tiles.


Been pulling a tile now and then, coverage is complete. Have seen warnings that all edges have to be supported, so have put enough mud to have it ooze up in grout spaces. Have scraped that out before it dries.

I have been mixing maybe 12 pounds of mortar at a time, using a 5 gal bucket and shovel.

Bud Cline
08-12-2001, 10:20 PM
Sorry sparky I misunderstood. I thought you were installing 1/4" slivers.

I still think if you are keying, then combing, the thinset to the substrate you should be getting a lot more distance from 50 pounds of thinset, even with a 3/8" trowel. Maybe I'm missing something else.