Leaks like it’s seeping out from under the tiles? If everything is done right you shouldn’t get any leaks and grout should last for a long time. If it’s breaking up you can try replacing the grout, but it shouldn’t be a continuing issue in my experience

Yes so like it would leak downstairs. Not sure if the guy who redid the flooring and tiles last time didnt do it properly or where the issue is but we're currently redoing the flooring and tiles again but would want to prevent it before it damages the flooring again

Are you sure it's leaking through the tiles? You would need quite a bit of standing water to get enough to soak through the grout, then into the ceiling of the next room.

Grout itself isn't waterproof though. Neither is the concrete under it

If the grout is intact and the water isn’t pooling on the tile anywhere it’s probably something to do with the drain/plumbing. If you’re tearing it out it shouldn’t be too hard to determine where the problem was. If you can’t find anything obvious I’d probably call someone with professional knowledge to take a look and see if they can identify the issue. It’d be more likely to be a spot where the floor meets the wall than just soaking through the grout unless it’s cracked.

There are waterproofing agents you can spray on the grout that will do a much better job of what you're trying to achieve without as much work, but I think the real problem is how much water you're spilling on your floor. That doesn't seem normal. A floor designed to catch and hold that much water on a regular basis would be pretty special.

I believe so.

We had a bathtub before but had the same issue so then changed it to a big shower (wet room) but had the same issue. Redoing it again but will have a glass door somewhere which will hopefully help isolate the water and direct it down the drain better

If this is intended as a “wet” room where water is expected on the floor and sloped to a drain, there should be a waterproof membrane between the sub-floor and the finished tile floor.

Either the membrane has a leak or someone skipped an important step in construction.

> Yes so like it would leak downstairs.

For it to show up downstairs, there must be a fair amount of water that is not making it into the shower pan.

If you have pools of water on the bathroom floor after you shower, the problem is not with the tiles and grout, but with your not containing the water properly in the first place. If this is the case, the simple solution is to determine the path of the water from the shower area to the floor and block off that path so that no water can escape the shower area.

If there are no signs of water on the flooring itself, then your next check is to make sure that the border between the walls and the shower pan is caulked properly.

Unless there are major portions of grout missing, this should not be an issue.

As others have suggested, if there isn't any visible pooling, it is probably a leak in the plumbling,

Grout is not waterproof and isn’t meant to be. Tile showers and floors aren’t sealed at the tile/grout level but from a membrane or pan under the tile.

So, I think the first and most important step is to actually identify where the way is coming from. For it to make it through the tile it would take a substantial amount of water sitting on it. You could try laying out some plastic sheets to stop it from getting to the tile and running the shower. Or if you are getting a lot of water on the tile, find a way to keep the water in the shower.

Please tell me they did a shower pan. You don't normally need one for a tub, but for a new shower, if they didn't do a shower pan, there is your issue.