My builder installed a frameless glass shower a 15 months ago. The glass goes up to the ceiling because the shower is also equipped with a steam generator. We have glass on two sides and limestone on two sides. The silicon caulking that attaches the glass to the limestone
At the floor of the shower seems to have contracted so that the caulking barely touches the limestone. The caulking that seals the glass at the top and the side is fine. When I open the shower door, the two glass walls tremble because they are not attached at the bottom. My builder hasn't returned my calls, so I guess I need to repair this myself.

First, do I even need to repair, or will a weather change make the silicon expand? Is this problem dangerous -- could the glass fall out, given that it is attached at the top and the side to the limestone? If I must re-caulk, must I remove the old caulking first, or can I caulk over it? If I re-caulk, will I have a problem if the weather changes and the caulking expands -- will the caulking become too tight?

I really need help! I have no experience in matters like these, being a single mom.

Firstly the what should have been used, and I think he did is 100% silicone. However this is not what hold that glass in place, there has to a track or brakes made from stainless steal to support this, you can get frameless doors I've seen, and the corner to not have any frame ,but attaching the glass with just silicone isn't enough.

As for recaulking, you need to remove the caulk completely, instead of caulking over it,
I say this because it want make a good seal if you just go over the old stuff,
They make a caulk remover, sales at Lowe's and homedepot, it's a green gel and you smear it over the silicone and let it disolve what it can then you can remove the rest with a plastic putty knife, 1" blade will do fine,

Well, I guess you need to do it yourself, because unless you had contacted him before the end of one year, as far as I know he (the contractor) would not be responsible for this. You may call him from an alternate phone number, because I know of an individual that will check their caller i.d. before they answer the phone and if they do not wish to talk to that person, then he will not answer.

My builder installed a frameless glass shower a 15 months ago. The glass goes up to the ceiling because the shower is also equipped with a steam generator. We have glass on two sides and limestone on two sides. The silicon caulking that attaches the glass to the limestone
at the floor of the shower seems to have contracted so that the caulking barely touches the limestone. The caulking that seals the glass at the top and the side is fine. When I open the shower door, the two glass walls tremble because they are not attached at the bottom. My builder hasn't returned my calls, so I guess I need to repair this myself.

First, do I even need to repair, or will a weather change make the silicon expand? Is this problem dangerous -- could the glass fall out, given that it is attached at the top and the side to the limestone? If I must re-caulk, must I remove the old caulking first, or can I caulk over it? If I re-caulk, will I have a problem if the weather changes and the caulking expands -- will the caulking become too tight?

I really need help! I have no experience in matters like these, being a single mom.
I am not an expert in this either but If you go to your local hardware store, they will have stuff that is similar to liquid nails only its clear like the silicone you are talking about. I don't know anything about climate changes and whatnot but if you read the label it will tell where it is applicable. Im sorry but I don't remember the name of the stuff, The price was around 7.oo dollars for 1 tube. That will be plenty for what you have in mind