We have a shower stall in our basement washroom. We moved in about a year ago, and it was not a very 'clean' looking job.
I cleaned out all the silicone in this shower stall, and reapplied it to where I thought it was needed. I also discovered that this stall is actually not one single piece. There is a base part from the ground to about 2 feet up. Then, one side of the wall has another piece of plastic and the other side of the wall has another piece of plastic that kind of connects like a puzzle (3 pieces total, and then the glass windows/doors). Anyways, I decided to apply a few layers of silicone, to ensure that no water would seap into the cracks where the 3 pieces of this shower stall meet each other.
I then, discovered that at the bottom corner of where the three pieces meet, there is a pretty large hole (you can probably fit a quarter in there), and just felt a very cold draft coming from it. Obviously, whoever put this washroom in place did not properly insulate behind it. I couldn't really put on silicone to cover this.
My question is, how do I properly 'plug' this hole so at least I can prevent cold air from coming through, and then put a good layer of silicone on there, to prevent water from doing any damage.