Leaking tub

Howdy,

I was hoping someone could help me. We noticed one day when we came home that we had a big water spot on the ceiling under the bathroom upstairs. In placing this it is below the tub. Well I thought that someone left the shower curtain open and it drained through a crack in the baseboard. Well it happened again a few weeks later. Went upstairs (this was right after a shower) and the floor was dry. But to be on the safe side I ran some new caulk all along the base of the tub.

After this it had happened twice more. I felt floor after shower and was dry. So 4 times in maybe 2 months. Here is the deal though. It has only happened after an adult took a shower. It has never happened after my young kids have had a bath, just after the shower. So I have a few questions.

1. I looked very carefully at the drain. It does not appear to have any broken seal. This I s a one piece tub/shower combo. Could it be that the larger weight of the adult would cause something to shift in the drain and only then would we get water to leak?

1a. If we give the little kids a bath, would not the extra weight of the water easily match an adult weight and cause a shift, or does that much water in effect form its own pressure seal.

2. As I said above, we have only seen this a few times. I assume that the leak does not happen all the time, could it be that it is leaking all the time? If so should we not see more “wet” spots (we see the spot as it as turned the white ceiling a brownish spot, but only 4 times have we seen it wet.

3. If only noticed after a shower, could water be leaking behind the handle or faucet (we have a handle that spins from about the 9oclock position to the three o’clock position) Shower head and regular faucet.

4. If it might be the drain, how does it come off? I unscrewed the filter for the drain and it seems that the actual drain part does not come off the tub. If this is the case the leak would be only accessed from the floor (ie ceiling of the floor below) I am really hoping I do not have to cut a hole in the floor as I have issues with even patching a nail hole.

5. Should I cut an access panel behind the tub/shower? It would be in the closet, so better than the ceiling, but will I even be able to access anything worthwhile?

Thanks.