I have what I'm sure is a basic question, but I haven't been able to find a reference in previous posts.

My single-hole faucet has become loose underneath my granite counter. Apparently, water has been getting in through the hole the past year and has left the wood underneath (plywood?) rotted and nasty and probably contracted.

When I mentioned it to a friend that was over, he suggested drilling a hole into the wood about a half inch larger than the faucet. He said that attaching the faucet to the granite was the way to go and that the guy who installed it was probably lazy.

So are all properly-installed faucets tightened directly to the granite? Are there any things I should watch out for, like over-tightening?