how to remove cement / adhesive from ceramic tile before re-attaching it to floor

I had to lift up two loose tiles on a bathroom floor. The tiles were installed about 3 years ago by a professional over a new plywood subfloor with a gray colored adhesive - or cement. I was able to remove the tiles easily without damage and need to reattach after drying the wood floor - some water got underthe tile. I have some extra tile but would not rather bother to rent a tile cutter etc unless really needed so I thought I could chip or scrape carefully to get some off. The tiles only have about one third of the surface wiht the cement.
Is there chemical that would help (phosphoric acid tile cleaner?) or do I just need to scrape? Do I need to get most of it off or just enough to be able to re cement it down and not have a high tile.
thanks
alan
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wrote:

to a stationary grinder. Makes a mess, but cleans off the adhesive, whether it is mastic or thinset (probably mastic if it was installed over plywood (not a good idea, especially in a bathroom).
Wear eye protection.
HTH,
Paul
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: I had to lift up two loose tiles on a bathroom floor. The tiles were : installed about 3 years ago by a professional over a new plywood subfloor : with a gray colored adhesive - or cement. I was able to remove the tiles : easily without damage and need to reattach after drying the wood floor - : some water got underthe tile. I have some extra tile but would not rather : bother to rent a tile cutter etc unless really needed so I thought I could : chip or scrape carefully to get some off. The tiles only have about one : third of the surface wiht the cement. : : Is there chemical that would help (phosphoric acid tile cleaner?) or do I : just need to scrape? Do I need to get most of it off or just enough to be : able to re cement it down and not have a high tile. : : thanks : : alan : :
At the risk of being flamed...
I'm currently installing tile and using a thin plywood for spacing. I'm have decent luck sanding the plywood spacers for re-use as I progress. I don't think that you are going to have any luck 'chipping' the dry material off. Likely you'll break the tile..
Unless others have a better suggestion...
Rick
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easily without damage and need to reattach after drying the wood floor - some water got underthe tile. <<<<
I would get a bucket of hot water and a stiff bristled (or wire) brush.
Just like the water loosened the tiles on your floor, water will loosen the 'thinset' and it will come right off.
Lewis.
******
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Thanks to all - all good suggestions. Now I will see what works best for me.
alan

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Alan Wrote:

You need to chisel off as much of the dried thinset mortar as possibl before resetting the tile. Acids will only harm the tile as well.
The best method still remains to cut a new tile.
You have an even bigger issue, however, and that is that the floor wa never properly prepared to recevie tile in the first place.
Tile should never be placed directly over a wooden subfloor, which i why your tiles are coming up from water after only 3 years.
Tile needs to be installed over a concrete based backer board or onto several inch thick layer of mortar.
Wood subfloors will expand and contract with moisture, especially i wet, and for this reason make unacceptable bases for tile.
Don't expect your repair to last if it goes back down directly ove wood subfloor
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ok thanks - What this means is that I really need to reseal the grout and keep the floor as dry as possible. I have had 2 different bath floors installed and while the original builder installed floors were in mud, the new ones were put on plywood after the mud was removed. Too bad I did not know this before.
alan
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pszwayka had written this in response to http://www.thestuccocompany.com/maintenance/how-to-remove-cement-adhesive-from-ceramic-tile-before-re-1629-.htm : what answer did allen get i have the same problem?
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On Dec 17, 2:36pm, elklakepaul_at_msn_dot snipped-for-privacy@foo.com (pszwayka) wrote:

you can use acid to remove thinset, but that's a messy and bad job. you can scrape it off. a good way i found was to get a cheap 4" diamond blade for a side grinder and use the side of the blade. it removes thinset really quickly and well. do it upwind as you don't want to breath the dust produced.
regards, charlie cave creek, az
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(pszwayka)

I did a shitload (specific unit of measurement in VT) of 2x2 tiles I had exactly this way. Worked out great. Best to wear some heavy gloves if possible and absolutely wear some type of safety glasses. It'll pretty much come off as a dust but chips happen.
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I get this job fairly regularly.
I usually use a putty knife as a chisel to knock off the old thinset. Sometimes I use a cold chisel to get off large chunks from the wall, but that's rare.
* Knock off as much of the old thinset as you can. You _must_ get off _some_ of it from the entire surface, or the new thinset will cause the tile to be proud of the surface. * Be careful not to break the tile. Put a thick layer of towels on your lap, set the tile on your thigh, and hammer on it with a putty knife. A flexible knife is safer for the tile than a stiff one, since it will bend and slip instead of breaking the tile. Neither of them is particularly safe for your leg. ;-) * Apply the new adhesive and set the tile in place. Thinset is good, but mastic designed for tile is OK too. I'd probably use mastic, because I have an open tub in the garage. Thinset I'd have to buy and mix.
* Don't put mastic on wet plywood--it won't set. I learned that one the hard way.
--
Steve Bell
New Life Home Improvement
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