You could have a leaking shower pan/drain or one of the shower water supply pipes could be leaking.

In our previous house our new shower started leaking into the garage below a few months after the bathroom was finished. My contractor came back and did several tests and determined it was the water supply pipe leading from the valve to the showerhead. When they installed a hanging mirror on the wall behind the showerhead they made a small puncture in the pipe. It was a slow leak that took a while to show up. My contractor was able to fix it by removing the mirror, making a hole in the drywall and patching it all back up. Worked perfectly after that. They were extra careful when they put the mirror back up! They also opened up the garage ceiling, made sure everything was dry and then closed it back up.

Your contractor needs to do a thorough test of every component. For example to test the shower pan, you use water from a bucket and not the showerhead ... you have to test each thing individually.

It defies common sense to think that the leak wasn't caused by the remodeling upstairs. Something wasn't hooked up right. It could be what the previous commenter described, or they may have not connected the supply or drain properly. You're actually fortunate it showed itself so soon.

Thank you for your responses. Validates my thoughts, esp especially with the contractor giving all kinds of excuses that this isnt related to his work in the bathroom.

Any insight into what should I ensure is done to the shower bed, any special tools / materials he has used to ensure the waterproofing?

It wasn't leaking prior to his work. It is leaking now directly under his work. Common sense says........................

" Any insight into what should I ensure is done to the shower bed, any special tools / materials he has used to ensure the waterproofing? "

Progress pictures? Flood test? Do you anything in writing what he was to use? See any packaging of any sort while he was working? Did he supply all materials?

Do you have any in process photos of the demo, waterproofing materials in place? Pros will weigh in and note if improper materials were used or critical steps were not done. What does your contract delineate as far as waterproofing and materials?

Shower floor and ceiling photos. unfor unfortunately no in process or material photos.

In the first pic why is one wall finished and the other wall cement board with red guard (not prepped properly btw)?

He was in the process of finish the red wall. we made him pull out the board to look for the prob when the leak started.

Did you mean there was anything additional to be done on top of the red guard?

The corners and all joints needed needed to be taped with non-alkaline mesh tape and covered with thinset (basically spackled), BEFORE the Redguard. Without that step the Redguard is practically useless. The way your is the surface may be waterproof but the seams are wide open and that is just for starters. How did he build the pan? How was the pan waterproofing tied into the walls when the floor is finished and the walls are not? What materials did he use? That alone does not give me a warm fuzzy about the rest of the shower, and give me the impression this guy is a hack. Add in the fact that he immediately got defensive and he is instantly proving my point.

What Millworkman said. Other than to add you will be ripping the shower and starting over. : (

Add Hack Man Exit Now, Please.

The waterproofing was not done correctly so a rip out and a redo of the whole shower . Really and please not the jerk who did the work the first time .This would be a good time to aslo rethink that tile with the shower walls not a good combo at all

Appreciate everyones inputs as I am a novice and really anxious now!

The boss contractor came in today and said the issue was with the exhaust pipe not being sealed. He said since we had the tab before, that pipe drained into the tub drain. The water was from the condensation happening in the pipe.

But now since we have the shower drain , that pipe is not needed and needs to be shut. He cut the pipe and put in a stopper and said it should solve the problem.

attaching a pic .

He mentioned the waterproofing is fine since he has a plastic material under the cement.

" The boss contractor came in today and said the issue was with the exhaust pipe not being sealed. "

How does he explain the complete lack of knowledge in construction the shower? You will have other issues with water leakage guaranteed. In light of the poor to outright lack of proper detailing I would call BS on this being a pipe issue. Unless the issue with the pipe is he has nothing left to smoke in it.

That is a complete redo with someone actually competent. I stopped counting errors at 7. Everywhere you look, it is wrong.