Answer if water from your shower is leaking into a crawl space the problem is not the cementitious grout joints.
Tile shower leaking around door.
It likely was not installed correctly.
If it s a shower valve leaking it s possible you can get at it from inside the shower but you may have to chisel away some tile to get it at for example.
Check the door seal a common source of a leak in a corner shower is the bottom door seal.
Determine where your shower is leaking.
The d i y video how to seal a big gap between tile floor and tile wall in a bathroom or shower.
All the caulk in the world may not prevent your shower and glass door enclosure from leaking.
Unfortunately the only way to fix this is to do the tile work over again.
One other sign of a shower leak behind the wall is the drywall tile in front of the valve becomes spongy.
In fact caulk can make it worse.
It shows how to seal a gap in the corner where the tile floor.
In a corner shower the shower head sprays water directly onto the door exerting more force and water.
Shower door leaks between glass.
Starting low on the wall splash or spray water on an isolated area and keep checking for leaks as you work your way up a couple of feet at a time.
If your door has a lot of gap as the bottom then you can install a frameless shower door.
If the shower drains and there is no leak then you will need to examine whether the leak is coming from missing grout between tiles on the shower walls.
Pfokus manufactures 12 different kinds of frameless door seals each with a different size and specification.
This is usually cause by water spraying from the leak in back of the wall.
To do this focus on one wall at a time.
If there is not enough of a slope back in towards the shower then the issue is likely being caused by the curb.
There has to be an underlying problem with the shower pan s waterproof membrane.
Failure to do so puts more moisture behind the wall or under the floor which can cause mold rot in the wood structure or crumbling drywall.
If your frameless shower door leaks from the sides then you can rectify this problem by installing a frameless shower door seal.
I have done posts in the past about not caulking the connection where tile shower and or tub enclosure meets the tub or the one piece shower base.
If your tile shower is leaking the cause of the leak must be found and addressed as soon as possible and definitely before you take a shower again.