Any chance you could get a tray like used to set plants on & caulk it in the window slanted toward the shower, you would probably have to use wood block or something to get it high enough at the back. but that would be neat if caulked all around so mold couldn't get underneath. You could get a piece of aluminum sheeting & undercoat & paint & put that in there well caulked so water simply runs into shower. It could be cut so that it fits tight against the window couple of inches from bottom of window glass slanting to edge of tile in shower & then you still have the window light. I would paint the caulking as it will want to mold & couple of coats of semigloss would slow that process down a lot. May need to go to metalwork shop to get the material you need. Could get piece of plastic from hardware store- Plexiglass cut to fit front(shower side of opening) & caulk it in place but I think it would be more prone to problems than the runoff tray of aluminum. Maybe shower area was dark & they figured window would help, or maybe Fla. room added later.

I researched this topic, studied the best way to waterproof and even found pictures and topics where people installed a small glass or plexi glass panel or "mini shower door". I ended up reconsidering creating the new shower in front of the old garden tub window because the shower spray would be directly hitting the window sill. I think that situations where a low and/or large window can be successful is if there is quite some distance from the shower head, for example very large showers. I suggest you ask this forum for help in redesigning your layout. There is awesome talent here - folks who very creative. They have a knack for getting the best layout out of very small spaces. They are very familiar with plumbing codes and also the available plumbing fixtures. So you may want to create a new thread with a title asking for help in your bathroom design.

@Nona Muss - I understand exactly what you’re going through. My first contractor didn’t do a pre slope under the pvc liner on shower floor. We got that addressed - and then he decided to not use any of the three bags of white thinset (he purchased) to install the carrara tile on the shower walls - but instead used mastic ”because it was faster.” When we pushed the issue, he packed up and left. The second contractor (with over 200 4.9 star Google reviews) sent over his “business partner” to bid the work. His “business partner“ then said that he felt so bad for me re: every thing that had happened with the first contractor (including needing to rip out the slate bathroom floor bc several pieces failed to bond), that he would start the work himself ASAP + work over the upcoming weekend. Well, it turns out that he wasn’t a “business partner” - but a new employee. He produced fraudulent receipts for materials (that I reimbursed upon recipt per contract) - and stopped showing up. I did a quick background check and discovered that he had been in prison for over nine years for aggravated battery + fraud charges (had been out for 18 months). I asked the owner about whether he had done a background check - he told me that he hadn’t run it yet. After I told him about the results of the background check I did, the owner asked me if I noticed the scar on the guy’s upper arm - and then told me that when he asked the employee about it, he said it was from “being shot by a cop.” I swear I am not making this up. He also stole some jewelry from me. Third contractor - great guy - had just started work - and then was sentenced to 90 days in jail related to a third DUI conviction. My fourth (and final) contractor is AMAZING. The third and fourth ones are both TCNA certified - I didn’t hire the first or second one - my SO did. Although I don’t blame him for what happened. My SO had glowing references from two of his law partners who had used the first guy for several projects + did research on the second one (who was the second highest bid out of five). I thought that by now I would have not only finished two bathroom renovations - but also my laundry room + kitchen reno (which is close to starting FINALLY). I actually wish I had never even begun - my bathrooms were fine - just a little dated.

Im gonna insult you likely. yet its not my intent. These scenarios happen daily to the point of being an epidemic within our industry on account of unqualified labor. A red warning flag to A homeowner is A handyman willing to do PARTS of a tile install especially A shower build. In the professional tile world we dont engage in these scenarios for many reasons. The biggest being liability especially when we wrrty our work. This combined with Installing rocks on A foam pan tell me this guy is not qualified to work on your shower. Every tiler knows there is a high likelihood of failure when installing rocks on a foam base. You are experiencing point loads and there is no fix. Most true pro tilers avoid foam bases completely yet many novices swear by them.. Your best bet is to completely tear it out and this next 3X MORE expensive time around source and hire A qualified tiler. There are still a few tile pros here on houzz that would be happy to help any homeowner source a tiler in their area. Its just that nobody comes here to houzz asking for hiring help. Yet they always arrive angry with the disasters. Homeowners reading along You Always want to place the entire tile process SOLEY in the hands of the tile installer. This means allowing them to supply every material and installing everything from the studs OUT. including the subfloor. Adding to that A solid written contract with a detailed scope of tile standards to be met and followed. as an aside: " You don't remove it; you tile over it which is a TCNA approved method. No waterproofing risk. " tile over a disaaster !!!!!!! Stick to countertop advice buddy XOXO