What went wrong here? DIY post-mortem
 

Hi, first post to this board. :)

About a month ago, my brother-in-law took up the old vinyl and tiled the floor of my small bathroom. He lives out of the area and was probably trying to do too much in a short period of time. When he left, everything looked great.

As I was caulking baseboards, I noticed the grout crumbled in places. I was afraid we'd walked on it too soon. But it was worse than that. We had used old grout (2+ years old), never realizing it had a much shorter shelf life. It crumbled and turned to sand when I rubbed it. So I removed all the grout and we were planning to regrout this coming weekend.

As I was making sure all the grout was removed, a couple of the 13x13 tiles just lifted right off the floor! It's a small floor (approx. 23 sq. ft.), but now 5 tiles have lifted off. A bit of the thinset is in the channels where the grout goes and I'm seeing where the (bad) grout seeped under the tiles. I'm hardly a tile expert, but it sure looks to me like the tiles weren't properly set in the thinset in the first place, judging by the pattern. Doesn't look like it got smooshed together at all.

I'm attaching a picture of where a tile lifted off. Do you think there wasn't enough thinset used? Or not enough pressure applied to the tile after placing over the thinset?

I'm guessing the whole job needs to come out and we have to start over. Can the old tiles be used? There really isn't any thinset stuck to them. Can we use the same backer board, or should we get a new one of those too?

Dang, it all looked so good for a bit.

Linelle,
It looks as though a V-notch trowel was used for the thinset. For a 13"x13" tile, it should have been a minimum of 1/4"x1/4" square notched trowel to ensure adequate thinset coverage on the tile. But maybe some of the more seasoned experts would care to offer their advice?
Keith

I would have to agree, wrong trowel. Also, are you sure thinset was used? From your photo it looks like mastic, although I could be wrong (I pray I am :sick: ).

Welcome aboard, Linelle. :)

Keith is onto it. There doesn't appear to be enough thin set on the floor. Further, it appears the thin set was allowed to "skin over" before the tiles were put down. That means the thin set partially air dried and didn't make a bond at all.

I would say you're looking at a re-do.

Thanks for the quick replies everyone. Wish I'd paid a visit here first, but I figured my B-I-L knew what he was doing.

I'm hoping "thinset" is a generic term. We used Ultraflex 2 by Mapei (prof. grade polymer-modified mortar) from Yardbirds in Santa Rosa, CA. This is what they gave us when we asked for "thinset."

As per Keith, should we have used a 1/4"x1/4" square notched trowel? We are using 13x13 tiles. Is that what I ask for in the store?

John, I think the skin-over part is what happened. Terry (BIL) was laying the tile, while his wife and I were cutting the tile in the driveway. It was a cold foggy day and she was drenched from the wet saw. Terry kept running out going, hurry, or the thinset will set up. Guess he was right.

Will I have to remove and replace the backer board too?

(edited to add) Does the thinset go down immediately before the tile is set? How large an area, using 13x13 tiles, is it safe to thinset at one go? How soon does it start to skin over?

Thanks again! :)

You can get 3 or 4 tiles down before the thin set skins over on you, but you can't mess around. You spread the mud and get the tiles onto-into it. Then do your adjusting. Don't screw around with one piece of tile while the rest of the thin set is laying there.

And the Ultraflex 2 is pretty good stuff. :)

No, you don't need to remove the backer board. You will need to use a little more thin set to cover the previous application, though. Get a 1/4 x 1/4 square notch trowel.

Another tip for good bonding is to comb out the thinset in one direction, set the tile, and then bed the tile in by moving it perpendicular to the thinset ridges. This will flatten them out evenly and give you good coverage.

And check out your B-I-L by pulling up a tile after he's set it and see. :)

Well, since I'm in a learning mode right now, can someone explain what's the difference between a V-notch and square notch trowel? Besides the obvious shape difference. Why did the (apparent) use of a V-notch on my floor contribute to its demise? Do they control the amount of thinset and its propensity to spread?

Hey! Stefan! If everybody did like you do, we'd run outa room on our server, eh?

You don't need to shout, we can hear you fine, buddy. :)

You guessed it. The size and shape of the notch controlls the amount of thinset left behind when the tile setter "combs" the thinset. It leaves a uniform layer, and the ridges assure that when the tile is pressed into it, the thinset flows and covers everything, tile and substrait.

Not enough thinset means that you won't get enough to stick to the back of the tile, which is bad for 2 reasons. 1) the tile won't stick to the floor, and 2) the tile is not supported enough to prevent point loads from cracking the tile. Obviously, you want to avoid both conditions.

V-notch is used for mosaics, or for other tiles where a lot of thinset would ooze up in the groutlines. Tiles that are not perfectly flat on the back could use a bigger notch than the 1/4 square notch, especially if you end up backbuttering all the tiles in an effort to get enough thinset on for good coverage.

As Stevan so coyly alluded to, pull a few tiles off and check the backs for coverage until you get a feel for the amount of thinset needed. Then pull a few every now and then to check your work and keep yourself honest.

In looking at the picture you should be able to reuse the tiles. There was no transfer of thinset to the tile since the ridges are very evident on the floor. However I would use a bigger trowel than 1/4 x 1/4 if this is a 13 x 13 tile. According to most thinset manufacters you should use a minimum of a 1/4" x 1/2" square notch trowel for tile over 12 x 12. When bonding large format tiles I will generally comb the thinset in one direction and firmly press the tile into the thinset and move the tile across the the ridges back and forth to ensure proper adhesion. This should ensure maximum coverage and ensure the tiles are properly supported. I would also re float the floor or scrape the thinset down before re setting the tile just to ensure a goog soung smooth surface to set on, and that should eliviate any issues you may have with the substrate tolerances

In reference to your last post, you are absolutly correct the obvious difference is the shape of the notch, however a v notch trowel is not reccommened for any tile larger than a 4 x 4 and is usually for small thin mosiacs. The V notch does not allow as much thinset at the top of the ridge so it doesn't cause an issue with thinset being pushed to far up into the grout joint causing a completely different set of issues.

Hope this helps,
Mike

This is great stuff. Thanks so much everyone! :)

Why would a larger trowel (1/2" over 1/4") be used for a larger tile? Do you need thicker thinset (thickset? :crazy: ) for a larger mass above it?

I'm planning to scrape the old thinset down. What does re-floating the floor involve?

the larger the tile, the larger the trowel required to get full coverage on the underside of it. Typically the edges of the tile will get thinset coverage first, while the middle body of the tile won't even have contact with the thinset(as shown in your pichers :sick: )

The minimum trowel that I will use for a 12" tile is a 1/4" x 1/4"x 1/4" square notch trowel, and that size is usually not enough trowel for the type of coverage that I like.

The tile needs to be fully supported by the thinset...no voids of air on the tile or else you run the risk of losing your bond(like in your picher).

Full coverage= Good
Voids and air pockets= re-install the tile

A larger format tile will span more voids or irregular places in the floor just because of its size it will span a larger area with more irregular areas. The larger trowel ensures enough thinset is on the floor to support the tile.

Floating the floor is just smoothing the floor out, this could be accomplished many different ways with several different materials. You will acheive the same effect by scraping the thinset off the floor and would be the best option for you in my opinion. The less irregular area in the floor the faster and better looking the job will be. The preparation will make your job much easier.

tiles 12x12" and bigger, I skimcoat the back of the tile, just to asure a better bond
I tryed to change the big letters, couldn't do it, don't know how :)

Gotcha covered, Stefan!


You can edit your own posts, and anything in square brackets is fair game for deletion.

My B-I-L got the rest of the tile up, and it really isn't a pretty sight. Of course, it would have been nice if they'd all not stuck to the thinset, but some did, breaking as they came up. I'm glad I didn't try to clean any of them up, since the tile is no longer available and I need to buy new ones. Just as well and not really the most expensive part of this project.

Some of the backerboard came up with the tiles, it looks like mostly outer layer. The board is screwed to the subfloor (plywood), but no thinset between them. The screws are mostly buried under the thinset that remained on the floor.

I need to get someone in here to redo the job. Can the new tile go over the backerboard in its present state, i.e., with some thinset remaining and some surface damage? I'm really regretting having a family member who doesn't live in the area do this. I would be livid with a real contractor, but family's more important than a floor and I have to let this go.

If the backerboard should be removed in the spirit of starting over, is this part of the work that a tile person would put into their estimate? I can't do this myself for more reasons than I care to go into now.

If I'm reading this correctly, you say there is NO thinset under the backerboard? If not tear it all out. The backer must have no voids under it. Not trowling thinset under it will pretty much gaurantee cracks in the tile and grout lines in a relatively short amount of time due to small voids under the backerboard.

Just to throw a wrench into things, I recommend a 1/4" x 3/8" square-notched trowel for 13" tile. I'd see if all of the floor tile can be pulled up to give you more confidence in the entire installation as well as giving you the liberty of using a larger notch than was first used.
Best of luck,
Shaughnn

Oh, all the tile's up, that's for sure. I'm buying all new stuff (the other tile was left over from a previous job 2-1/2 years ago and it's not available anymore). The existing backerboard, besides not being thinsetted to the subfloor, looks like crap. I want the legacy of the old job-gone-wrong completely out of there.

Is removing old backerboard something a tile person will do? Or do I have to hire a backerboard removal guy?

(Hey Shaughnn, it looks like you live in my neck of the woods.)

Hi Linelle, sorry to hear about your floor. Sounds like the gang has you headed the right direction. A tile installer can remove the backer board. It's a matter of getting a small crow bar under it and prying it up.

I like the idea of putting a skim coat on the backs of each tile using the flat side of the trowel and spread the floor using the notched side. :)

Hi Linelle,
Taking up the backer board is tedious, but it's not rocket surgery. :) If it was put down with nails, they need to be pulled and I find a "cat's paw" is the best for that. If it was screwed down, just fine the heads and clean them out enough for a bit to get in there and unscrew 'em. Yup, we're neighbors in a way. I'm in Vallejo. Where do you plan to buy your new tile? You've got a good little tile mecca there in Santa Rosa. And with Sonoma Tile works in Windsor and MacIntyre Tile in Healdsburg, you can deffinately find quality if you have the interest,... and the budget.
Shaughnn

Shaughnn, I was gonna say "cats paw" but didn't figure anyone would know what I meant. :) Perfect tool for digging out those nails.

The backer board is screwed down. I don't know what they're called, but the screw head has a little square in the top. I have gotten 3 of the screws out. A few more are visible, but their little square is filled with thinset. The rest of the screws are covered by thinset. Theoretically, if I could find the screws and remove them, the backer board should pretty much lift out (except for where the toilet sits on it). But if I can't find the screws, I'm at a loss (or screwed).

What's a cats paw (other than the twelve at my house currently attached to cats)?

I'm probably going to get my tile at Santa Rosa Tile. They've got the color, the price, it's all in-stock, and let me take sample tiles home without charging me. And they don't hover over me when I'm just looking. :)

Davy, I know what you mean, most people around here look at me funny when I mention a "cat's paw" tool.

A cat's paw looks like a regular crow bar with the business end modified into a pair of curved, pointed ends. This end is shaped so that when you whack the blunt back of the cat's paw, the cat's paws are driven deep into the wood where the prongs straddle the head of a nail, whereby you can then pull it out. I think it was named when someone saw a cat pulling a mouse out of a hole in the ground.

Unfortunately, this isn't the best tool for pulling out square drive screws. Go ahead and give it a chance....maybe the screws he used are standard black phosphate drywall screws...... :) ......Not the right screws to use, but may make it easier to pull out. (They are not tempered, so they are brittle...and they are small and will rust). I would grab an "ice pick" which is like a standard "awl", but a bit pointier. They are good for diggin' the mortar out of a screw head so that you can back those buggers otta there. Be careful with that thing, though.

And the screws you are describing are most likely #2 square headed screws. Get a #2 square head driver and chuck it in your drill.

Linelle,

If I understand, you & spouse cut the tile first time around? I learned a good tip for eliminating the thinset skinning over. Thanks to the fine fellas here. :bow:

This works real nice in a small area.
1. Start cutting your tile like you did before.

2.Get your handy tile spacers out ( little1/4" X-looking things).

3.Start dry laying your tile with spacers, even the full tiles. Dont forget your little gap along perimeter of tile field for caulk.
You can take all the time in the world and get your precise measurements.

4.Once you are happy with all your cuts, go mix the thinset. :dance:

5. Do whatever else the mods say. :D

This is how I did my first (small) tile job recently. Believe me I was ascared of thinset and screwing up tiles. But it came out pretty darn good! :)

If I can do it, you can do it. :cool:

I agree with 3 and 4 even with 18 years exp so much easier. 1/2 x 1/2 inch for 12 inch tiles. The big problem is controlling thinset bleed up in joints. If tile is installed systimatically that factor will be minnimized. I can elaborate if requested to. Use the spacer for scraping bleed if any between the joints then pitch it follow up with a sponge.

I make this comment just to hassle Glen. :stick:

With 12" tile a 1/4" grout line is perfectly acceptable. So, (I think) is 1/2" grout lines.

Personal preference, asthetics. Glen, why do you prefer 1/2"? Just curious.

My little project with 12" tile and 1/4" grout lines in picher. Thinset squishing up was very minimal. :)
Dyanne

Say Dyanne,
I don't want to alarm you but it looks like there's a sinkhole in your pottyroom. Is that a register in the middle of the floor? Maybe I'm just pampered but I've never seen one placed like that before?
Shaughnn

Shaughnn,

Well that register used to be right along wall.

Gives an idea of how tiny this bath was. :laugh2:

It now comes out the new cabinet toe kick, so we didnt have to move it that much

Thanks Dyanne,
It just looked out-of-place to me, is all. Kinda like a postal slot where you don't want to be sending any mail from. :p

Actually it's the laundry shute. :uhh:

No really, it's invisible now.

You dont know its there unless you happen to be lying down on the bathroom floor.......at which point you are probably not interested in toe kicks and things:D

1/2 x 1/2 inch trowel for 12 + inch tiles. Usually 3/16 or 1/8 spacers.

Glen,

Oh, 1/2" Trowels! My bad, :o thought you were refering to the 1/4" tile spacers I had mentioned in #2.

Thanks for clarifying, I was was in tile limbo there for a minute! :rolleyes:

Dyanne

I have 1 good eye left :stick: please dont poke that at me again lol I am not a voodo doll.

poke, poke (hee-hee!)
 

Glen,

Guess I better be nice- I might need your advice before it's all said and done! :rolleyes:

Anybody seen linelle? Or are we just talking amongst ourselves, here?

Dyanne

Y'all prolly run Linelle off. :)