Acrylic Shower Kit Holes at Bottom of all Walls - Purpose?

[Skywriter]

Can anyone tell me what the purpose is for these cutout holes at the bottom of the shower kit walls? There are three on each of the three walls and one on the inside of the right entry casing. This shower was already installed when we bought our house 14 years ago, so I don't know anything about the kit or how it was installed. There seems to be another layer or acrylic behind the holes.

There is also a lip around the base of the shower where it meets the walls. There was sealant (not sure what kind) over this lip and most of those holes. I have removed all the sealant, which was failing (falling out in some places and turning milky in others) anyway. The design of the shower seems to be for any water that gathers in the lip at the bottom of the shower walls to run around to the little ramps at either side of the entryway and then flow into the pan and down the drain. That is, if the install was done correctly and levelled as it should be. But, either way, I figure any excess water in that lip should evaporate naturally.

I am wondering if the 10 holes at the bottom of the exterior walls should not have been sealed. I removed that sealant as well. I'm not 100% on this one, but my theory is that these are either:

1. vent holes to allow any moisture that might find it's way behind the walls, to evaporate. But of course having the holes open will allow moisture behind the wall, so I am not feeling very confident on this one.
   
2. these might have been designed as overflow outlets, like what you have on most bathroom sinks. I tested this, by blocking the drain, and unfortunately the water did not drain out these holes. So, either my theory is wrong, or maybe the installer did something to make this overflow action impossible. Regardless, even though water did not drain out these holes and down the drain, it also didn't drain out these holes and go anywhere else so that is a good sign, I guess.

I'm hoping for advice on whether to seal these holes or leave them open.

Thank you for your time and expertise.

 

[Skywriter]

A quick follow up with more info.

This shower install is very small, only 80cm x 80cm (31.5"x31.5"). Is it possible that this could be an RV shower enclosure? Would these holes be used for something specific to that application?

I have searched in vain for days for an explanation for these holes, and can't find a single lead.

Any help would be greatly appreciated.

 

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[WorthFlorida]

The wall panels were probably installed upside down. These look like pre drilled holes for the shower arm and there were probably caps provided that went over any unused hole. But maybe not. The wide picture I don't see these holes/

 

[Skywriter]

Thank you for your reply.

I may be wrong, but as best as I can tell, the walls and floor pan are one piece. You can see in the first and fifth picture, where the wall meets the pan that there is no joint sealant. There is some dirt, but if I push on the wall, there is no movement at that joint. Unless it's sealed/secured from the outside?

Would pre-drilled holes for the shower arm be only 1/4" diameter? And would there be one on the entry casing as shown in image one? Is that common. I have no idea.

The holes are at the bottom of the wide picture, they just aren't clearly visible. You can see their location in the third wide image.