leaking shower enclosure (cracks in sealant)

[charlesa]

Good morning all. My shower enclosure is leaking and causing damp to seep through to the ceiling below. The grouting/sealant is cracked where the shower tray meets the vertical wall as well as along the vertical corner seam. Could someone please advise me how to create a waterproof seal that won't crack again ? Many thanks in advance.
Best wishes, Charles

 

[ChrisR]

Remove off all the silicone, scratch deeply to remove tiling grout wherever it gets wet. (Plasplugs carbide wedge shaped tile scribe is the most efficient tool I've seen for that)
Regrout with waterproof flexible grout
Resilicone with top quality stuff, having cleaned scrupulously with meths.

Guaranteed? Nope.

Also check it isn't the waste which is leaking. (put a hose in the tray)

 

[jobloggs]

To add to Chris's excellent advice: It might be useful to add weight to the tray equivalent to your bodyweight while the silicone is curing. This might help if the floor is flexing excessively when the shower is occupied.