Tile floor buckling

[jmagerl]

Heard a loud pop last night and this morning I found 4 ceramic tiles buckled like pavement on a hot day. The floor is 20 years old and was installed by pros. Tiles were 8inches square

The adhesive was thinset with about 1/3 stuck to the tiles and 2/3s to the floor. The tiles were installed over plywood. The thinset left on the plywood is easily scraped off with a putty knife.

Ignoring what caused them to pop up in the first place (I don't know), whats the best way to stick them back down? Mastic comes to mind but I think there will be height difference between old tiles and new due to the thickness of existing thinset. I'm having a hard time believing that thinset sticks to plywood if I use thinset. How do you get thinset to stick to plywood?

I suspect from the sound of the floor that there are other tiles beginning to loosen up. Is this normal for thinset over plywood.? The floor seems pretty rigid with no squeaks. From below it looks like they used a nail every 6 inches to hold the plywood down.

[Steve B]

IMHO, if you got twenty years out of thinset over plywood, ya dun good.

Steve

[chickenwing]

keep it simple, get some liquid nails, plopem back down

Merry Christmas

[Sacramento Dave]

would be expansion causing them to pop loose after 20 years. but their also had to be a lot of hotter days in 20 years so it could just be material failure. My self I would not use thinset on plywood. You say you think other tiles are lose sounds like it's time for an upgrade. .

[m Ransley]

Either wood floor contraction or expansion or house settling, being winter probably contraction to low humidity. Maybe as chickenwing said fix it easily till you decide what to do

[Bill]

They were anything but pros. That is why I hate to hire anyone to do anything to my home! Should have been thinset to cement backer board to plywood as a minimum. Heck, if they were "pros" they would have done a dry morter bed first. As was posted, I'm amazed they lasted 20 years as well!

Just for you future info - plywood expands and contracts and also absorbs most of the moisture out of the thinset during the install.

-- Bill

[RicodJour]

You think it's wise to ignore what caused four tiles to buckle overnight? I wouldn't spend any effort on resetting tile until I found out what the cause was.

Where exactly were the tiles located in the bathroom?

R

[chickenwing]

I think she knows a little more than she's telling

[mstrspy]

My bathroom floor tiles were put down with thinset over od hardwood floors. They have been lifting and loosening for years. I stick them back down with floor tile adhesive. Seems to work, but what a pain. Thinset must be garbage. Seems like it is a problem. M

[chickenwing]

it really just depends on the subfloor

the real test for a subfloor, is to jump up and down between the joists...see if the floor gives...and how much it gives, also see how much bounce you can get from a joist system. a bouncy living room is a yellow flag..that system would need some extra peirs under them...as needed.

try tightening up the floor where your tiles are cracking.

the floor is moving

[RicodJour]

The garbage was the plan on setting tile directly on hardwood floors. Thinset is not the problem. If they've been lifting and loosening for years it's time to redo the floor correctly.

R

[chickenwing]

yeah, i've never heard of setting directly onto hardwood I don't see how any mortar would bond to a hardwood

or WHAT some numbnutz was thinking when they put it down i'd like to have a word with them by God

[Keith Williams]

Yes, thinset is junk, like everything, if used incorrectly. Thinset is *not* intended to be used with a plywood substrate, much less hardwood flooring. Rip it all up and do it right.

[RicodJour]

The Tile Council of America, and most thinset manufacturers I've run across, allow thinset on plywood for light, dry, residential foot traffic. That being said, I think it's a piss poor way to go.

R

[chickenwing]

on the bag of mortar is says, ideal for ext plywood substrates ideal is just peachy..so long as plywood does not move or get wet too much

[Keith Williams]

The modified thinset I used discouraged plywood, but said that it could be used if it was sealed. If not sealed it would likely dry out the thinset.

Agreed, though the builder (I assume) of my house did it. I just tore it all out this summer. What a PITA. Many tiles were loose and I decided it was time to start over. Half the tiles were stuck tight to the thinset. The other half the thiset was stuck tight to the subfloor. Little was fastened securely. I ended up replacing a couple of sheets of subflooring. Did I say it was a PITA?

[chickenwing]

agreed, they should not have come up so easy any glue will work, i've repaired cinderblock with subfloor glue (where's it going)...

most of the time people walk and their tile too soon it takes a good 2 months or more, for a wet job to fully cure...given the room and floor dry around room temp

if you seal the floor before 2 weeks expire, you are sealing moisture into the floor it will eventually get out...but it will take that much longer

where can moisture go except up...and into your substrate / then where does it go... it don't, it stays there, it softens the floor, we walk on them too soon.

we should, take a vacation while the tile dries

someone says...ah hell you can walk on that! you can? but it ain't dry...

I always read mfg instructions (now I do)... it gives me a solid answer for my customers

I don't insist on anything, I have to walk on my floors but I know how to weigh 30 lbs less on my tile while it's curing

[g.a.miller]

You need to put down hardbacker sheets over the plywood to elimate the tiles from all popping. In other words you need to pull up all the tiles and start from scatch sorry! Anthony

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