Percival P. Cassidy wrote:

On 10/21/08 12:42 pm Norminn wrote:

For a while after we moved into this house the shower stall looked
fine, but then the grout lines -- especially those between the edge of
the floor and the bottom of the walls -- started looking dirtier and
dirtier.


snip

I've just started attacking the grout with a grout saw, with the
intention of regrouting those joints, but it appears that the previous
owner used silicone caulking compound over the existing grout along
those edges. This complicates cleaning out the crevices. And even
where I've managed to clean out the old grout and caulking compound,
everything is still black, and even straight bleach seems to have no
effect.

Any suggestions about the best way to deal with this?


I regrouted our tiled shower stall with good results, about 4 yrs. ago.
I used the Dremel with special bit and guide. Only tough part for me was
kneeling for the low spots and using enough pressure to regrout (I'm old
) The black stuff you find is bothersome, and I hope it is from the
previous caulking applied over dirty old grout and not from a leak that
has saturated the wall. If you get through all of the grout and still
find blacfk mold, I've be very concerned that there is a leak behind the
wall. Any chance the original grout was black? When you get it cleaned
out, use full strength bleach, rinse well, and dry well before you
regrout.



Thanks for the suggestion, I did not know about the Dremel bits. The
1/16" one seems to be doing a good job. I', mot using the Dremel guide
because I don't have a genuine Dremel tool: I'm using a
battery-powered B&D. (IAC, I couldn't even see any genuine Dremel
tools with the model#s the grout removal kit was intended to fit.)

Any ideas on getting rid of the silicone caulk residue?

Perce

Someone else pointed out that there was a 1/16" tip, which is likely the
one I used that "grabbed" in a few places where the tiles were too
close. We have a very old, and a much newer Dremel rotary tool, and I
used both on my grout job. As for the silicone caulk, if it is on tile
I would use a razor blade scraper (with fresh blades). I've never used
any of the chemical caulk removers.