On May 24, 9:48*pm, RicodJour wrote:
Too thin of
a grout line is as bad as too big of a grout line in wet areas. *Go
with the spacers - 1/8" or a bit more is about right with 4x4 or 6x6
tile.

He states he's replacing a section, and seems to be detail oriented,
so he probably wants to match what's there.

He could use anything for spacers horizontally, vertical isn't much of
a problem to eyeball.

The other problem with thin grout lines can be filling the space all
the way to the substrate. An unsanded grout of lighter than usual
consistency would be my choice.

My theory is that most modern grout jobs fail due to failing to dampen
the joints before grouting, followed by failing to fill the joints,
and/or poor basic construction.

Which brings me to failed grout. The only reason I know of that grout
should fail is excessive flex of the substrate. In that case, no
grout job is going to last.

Any such major tile repair should be carefully evaluated against
complete replacement, and I wouldn't suggest the former be tackled by
homeowners, except that the chance of finding anyone more qualified is
exceptionally poor.

There are tons of little tricks a "real" tile mechanic employs that
nobody told the clerk at HD. In this example it might be beating in
the new tile from a base on the existing tile, or recessing the new
substrate a hair and building it up with thinset to make it all come
out flush, or washing out the corner joints just a hair to leave a
little more room for caulk, if you think it's necessary.

All depends on your expectations of the finished product, I guess. A
good tile job is expensive, a homeowner can get comparable results
with due diligence.
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- gpsman