silicone or acrylic caulk should be used ONLY as a water seal to prevent leakage.

the sink itself should be supported using mechanical means - either via
clips installed into the underside of the stone, or via a cradle mechanism -
holding the sink in place from under the sink.

an undermount sink should never be installed using ONLY a glue to silicone
bead to hold it against the underside of the stone - that's what pretend
fabricators do.....

call your fabricator back to address this at once.... be assertive but be nice -
they could have just made an honest mistake.....

HTH

kevin

Kevin - the sink is installed using clips - what I really need to know is should there be a silicone caulk as well to seal between the sink and countertop? Because right now there is just open space.

nekothecat - ours was installed on Thursday. After the granite was in place and the sink secured, my installers did put a bead of clear silicone between the sink and counter, smoothed it in and wiped it down. It's not too visible, I just happened to watch them do the whole install. Good Luck.

Yes, there should be a bead of silicone between the top of the sink and the counter edge, to prevent water getting under there. Easy to do yourself - just get good quality 100% silicone caulk.

Sorry for the late response - it's 6:45am here in PHX........

Circuspeanut said it 100% right.... YES you DO need a bead of either
Silicone or Acrylic Caulk to act as a water barrier / seal - between the
top rim of the sink and the bottom surface of the stone.

You can either have your Fabricators come back to do it (which is what
I would do if I were you - YOU paid for this to be done right in the first place)
or..... you could do it yourself if you're so inclined......

HTH

kevin

As long as this subject is here, what IS the difference between acrylic versus silicone caulk?

acrylic is water based - 100% silicone is not....

either will work - if your doing it yourself - acrylic is way easier to finish
with a wet sponge or rag than silicone.

100% Silicone on the other hand has a much more tenacious bond to a sink
and to stone, and must be cleaned off (when it's just been applied) with
de-natured alcohol. Silicone also has a really strong vinegar smell when
it is applied - but that goes away after a few hours of curing.

we use 100% Silicone - because I've been working with it for close to 35 years.
Usually I use either GE, Dap or Dow Corning - I don't waste my time & money on the "Silicone II"
or the "Siliconized" brands - for me - 100% Silicone is the way to go.........

Acrylic is easy to use, but silicone will last longer IMHO

kevin

Thank you. I seem to remember something about that silicone doesn't bond...to itself? to other substances? maybe paint? Maybe that was just for caulking around a tub? Maybe...

Who knows, but I appreciate you clearing that up.