On Jul 20, 5:39 pm, Alex wrote:
Hi all -

Getting ready for a ceramic tile install this weekend in my basement & ran
into a possible last minute "uh-oh"

...I'm installing 13x13 tile using VersaBond thinset from Lowes over part
of the concrete slab in my basement. Someone just mentioned to me that it
can't be installed over a sealed concrete floor.

I _think_, but am not entirely sure that the floor was sealed after it was
poured around 10 years ago. On the VersaBond bag it does say to remove
sealant before applying.

I did a test with some water on various parts of the area I'm going to
install the tile. When I poured the water onto the concrete it did pool a
little... but after it either all soaked in (for smaller pours) or I wiped
it up (on the larger pours), it did leave the concrete a wet color. Some
of the dark areas were uniform in color, others had a snakeskin sort of
pattern going on.

Will I be ok putting down the thinset as long as liquid does absorb into
the floor - and leave it discolored - basically leaves a 'wet spot'?

Thanks!

Can you run a floor sander to roughen up the surface? That's what I
did on my garage floor before installing an epoxy coating. I could not
positively verify whether it was sealed or not. It took just 15
minutes using a rented floor sander.