How To Remove Thinset From Ceramic Tiles
Well, we have good news and bad news on this one. The good is
that it can be done. The bad, is that it will take a great deal
of time and patience, and in the end may simply not be worth it,
especially if you need to keep all the tiles for re-use, and
some get broke in the process.
The two adhesives for attaching ceramic tiles are organic based
mastic, and the cement-based thinset. Mastic is not used where
there will be a great deal of moisture, because it tends to
absorb it over time, and loses its bond. It has been used
successfully in shower stalls, but depending on the quality of
the installation, may only last 3-6 years.
On the other hand, thinset being a cement product, does not
absorb water, and is longer lasting for use in areas that will
have high levels of humidity and lots of water. Unfortunately,
that also means there are few options for removing it. It will
not break down when soaked, and there are no chemical removers
for cement, as there are for adhesive.
If you have managed to remove tiles intact, that were anchored
with thinset, you are to be congratulated. This is a feat in
itself. Tiles are simply a refined clay that has been baked for
a certain amount of time, at a set temperature, which will
determine its compressive strength. But it is not a flexible
material, and has very little tensile strength, or flexibility.
That virtually eliminates using a chisel or even a putty knife
to try and chip or lever the thinset off the tile. Your only
real option is to grind it down, as gently as possible, with an
electric sander. Not only is it difficult to fix the tile in
place so you aren't grinding off the back of it, but it is a
delicate and time-consuming job.
If the point is to repair a spot, or to re-use all the tile you
have, chances are that you will come up short when some get
broken. In that case, try using a complementary color or design,
and create a pattern, border, or shape with the new tiles, that
will supplement the old tiles you saved, so that you have enough
to complete the job.