Water under tiles in a tiled shower

Is there a way to find out afterwards whether it was sealed? Apart from removing the tiles and looking under the tiles?

If you understandably no longer trust the tiler and also do not have sufficient knowledge of the proper execution, I would immediately consult an expert. And do not use the shower for the time being until this is sufficiently clarified. I also would not try to fix it or make any adjustments yourself, in the end the tiler might quickly shift the blame to you.

First, I would check the slope in the shower towards the drain. Use a small spirit level and check whether the water is flowing against the drain or even standing there.

At the joint between floor and wall at the back, I would glue a rail instead of the joint with body filler Sika Flex or similar.
Then the connection would be sealed. I would also seal the other connections with body filler instead of silicone.

There are semi-circular sealing rails for the corner area.



But first check the slope, otherwise everything else makes no sense.

What use are superficial sealing measures if no waterproof coating was applied behind the wall and floor tiles?

I answer my own question: nothing! (or only a few days/weeks) until the wall behind is soaking wet and mold starts to grow.

Fixing a paid craftsman's mistakes yourself now would, in my opinion, be catastrophic as already wrote.

The only correct measure: expert assessor

Only correct measure: expert

Best to immediately send a team of lawyers after and really tear the tiler apart.

What is the expert supposed to do? Does he have X-ray eyes?
He will break off the tiles to see what was done underneath. What if everything is correct? Then it will be expensive for the owner of the house.

As said, stick a few stainless steel cove rails in the corners, then there will be peace for many years. I would never seal such stressed corners with silicone.

What is the expert supposed to do? Does he have X-ray eyes? He will hack away the tiles to see what was done underneath. What if everything is correct? Then it will be expensive for the house owner.

It is clear that it has to be checked. Because something definitely cannot be right, otherwise this problem would occur more often.

As I said, stick some stainless steel cove strips into the corners, then it will be quiet for many years. I would never seal such stressed corners with silicone.

Completely my humor, I build new and pay a lot of money for my bathroom, only to fix a problem caused by some DIY tinkering while I am still under warranty. Attaching some strips is just patching the symptoms; the cause is not fixed by that. I repeat myself: Something cannot have been done correctly there.

Only correct measure: expert

Best to send a lawyer team right after and really take the tiler apart.

What is the expert supposed to do? Does he have X-ray eyes?
He will hack off the tiles to see what was done underneath. What if everything is correct? Then it will be expensive for the homeowner.

Right, it can become expensive for the OP. If the tiler messed up, there’s no guarantee he will take responsibility for it. The expert must at least be paid by him himself. Getting reimbursed only happens in court if he wins (not in a settlement) or if the tiler has a change of heart. BUT: If this mess is not repaired properly, consequential damage can be much higher. Then 2 to 5K no longer matter (do we even know how the OP built? Solid construction, timber frame, etc.) It’s definitely bad. And it’s NEVER correct to patch silicone over silicone!

As said, stick a few stainless steel cove strips into the corners, then there’s peace for many years. I would never seal such highly stressed corners with silicone.

Exactly, the coves are then sealed. But the normal tile joints are not (permanently) sealed. That’s how it is, you can read about it if you want. The only thing that helps is the waterproofing layer behind the tiles and appropriately applied collars / tapes on edges and in corners. Why do you want to advise the OP to such absolute nonsense? Just to boost yourself? I’m no construction expert, but I can at least share my own experience regarding my young new build. And exactly on this topic, our tiler had to pay the glazier for extra work because he forgot a collar (around the faucet). In solid wood construction, you can literally tear the house down if there is mold behind it.

I’ll leave it at that now, the OP is grown up and can hopefully decide for himself what is right for him.
No one is forcing him to consult an expert, it is only strongly advised since he apparently isn’t familiar with the matter.

That so much water is pushing upwards and has not already found its way into the wall or across the floor into another room (where is the shower located?) rather suggests that the sealing is present and holds. However, this does not change the measure to be taken, because a cavity where water can accumulate over a long period and cannot dry out must not exist.