Our granite installer did a hasty and poor-quality job with the silicone seal between our granite counter and the undermount sink. There's now something growing behind it; I can see it, but can't scrub it out, even with a narrow brush that exactly fits in the crack.

Is it a sign that the seal isn't good, and that further problems await down the line (ie, water getting past the sealant, dripping down the sides of the sink, and winding up in the cabinet)? Is it unsanitary? Am I loony to think I should strip out the sealant and try redoing it myself? If I should, what tools and supplies do I need for that? I don't want to call our installer back; it took him two visits, complaining all the while, just to do the subpar job we're stuck with now.

Alternatively, feel free to tell me that I'm worrying about something that doesn't need to be worried about. That's the outcome I'm hoping for, to be truthful.

Oh, one more thing. This same installer grouted, but didn't caulk, the granite where the countertop meets the 4" backsplash. He said the grout needed to dry first, and that once it did, *I* should caulk it, with clear silicone. I haven't yet. It looks like the grout is shrinking -- it doesn't fill the cracks the way it used to. I'm thinking I need to get going with the caulk. Consensus?

TIA for all these probably-idiot-level questions.

No, the opposite is true.
The backsplash mounted in the wall, and the granite on the cabinets will not move together. A flexible joint is thus required between the two surfaces to allow for small movement without breaking the seal to each surface.
The same condition applies in tiled walls and floors. The wall to floor joint should be caulked, never grouted.

I was surprised when he told me that *I* should caulk over his grout seal. This is a guy who was recommended *very* highly by a lot of people: I called every single person on his references list and asked a lot of very critical questions. No one, not a single person, said, "he expected us to finish up the job; he told us to caulk our own counters." ISn't that part of the installation?

Anyway, I think I know the answer to that. And given that he whined when we asked him to come back and re-seal the sink (which he messed up the second time as well as the first time -- all the while complaining that no other homeowner had ever asked him to do this, and that the sink is not his responsibility), I don't want him back in my house, because I think he's a jerk.

So: sounds like I should recaulk the sink seal and caulk over the grout he laid. Yes? I'm going to use clear silicone and masking tape, so it looks nice. Any other tips, advice, cautions? Pamkcs, did you just rip the old sealant out with a screwdriver and clean what was behind it?

As before, thanks in advance!

You can shape the silicon caulk with a wet spoon or a wet finger while it is still wet. Put the tube of caulk in a caulking gun, cut the tip at a 45 degree angle and so you end up with a three eights inch or slightly bigger hole at the end of your caulking tube. Put the tube at a forty five degree angle with the nose in the crack with the long edge of the hole facing down. Push the caulk in front of the tube and push it down into the crack. There should be just a bit of caulk visible in front of the nose as you go along. The tube will run over it and shape the caulk as you go along and you can use the wet finger or spoon to clean it up more if it needs it. If it is still difficult to keep tidy, clean up the edges and the strayed bits with a single edge razor blade after it has dried.

A hui hou,
Cathy

See my solution on this link:
http://ths.gardenweb.com/forums/load/repair/msg021329079553.html
See my picture on what I was dealing with