Answer answer if water from your shower is leaking into a crawl space the problem is not the cementitious grout joints.
Shower tile floor leaking.
Apply a second coat to the same.
To waterproof a shower pan and shower walls you have to have a waterproof membrane that meets ansi a118 10 to be properly installed.
It likely was not installed correctly.
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.
Fix a leaking shower valve.
If you find some you re in for a new shower pan or shower floor to stop the leak.
If built correctly a shower floor built over a mortar bed can be long lasting and reliable.
Application of shower plug to fix a leaking shower floor.
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.
There has to be an underlying problem with the shower pan s waterproof membrane.
If this is the case remove the damaged section so that you can replace it with new material.
Check for cracks even very fine ones anywhere on the pan.
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.
Shower pan leaks leaky shower floor if your water leak is coming from your shower floor then it may be obvious already you have a broken shower pan.
To do this focus on one wall at a time.
First most brands of shower valves use similar methods to install the valve.
When you turn on your tub shower valve the hot and cold water enter the valve and mix to the desired temperature.
If your pan or floor looks good try this basic step.
If your initial leak was indeed coming from below the bathroom tile chances are that there is considerable water damage to the wall or floor.
For this we will apply shower plug sealant.
Leaky tiles can occur anywhere where water is used whether it s a shower a wet room or a kitchen splashback.
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.
Understand and fix your leaky tile shower pan to get rid of mildew mold and rotting wood.
However the complexity of the process can cause many issues down the road if several key steps are not properly executed.
They can often cause damp and mould within surfaces behind tiles and can even threaten the structural integrity of walls so it s important to tackle the issue at the first sign of a leak.