One of the first issues people have with shower rooms is the Silicone needs to be replaced, even a good quality Silicone like Mapei Ultra-seal which is fully waterproof and stain and mould resistant can still succumb to persistent damp issues. In fact it can get so humid in these areas the warm atmosphere is akin to a tropical rain forest.
To avoid the build-up of mould I recommend you rinse the wall tile and silicone down with plain water from the shower head after every shower and then leave the tiles to dry. Open the window and door to let out the warm condensation and after 5 to 10 minutes partly close the window (to the security setting) and then partly close the door, this then normalizes the room temperature thus inhibiting mould spores from blooming, as mould wont start to Spore on a cold room.
The pictures were taken from a shower room at a house a few miles up the road in Kendal where mould had caused a lot of staining to the silicone sealant and to the tile and grout both inside the shower cubicle and in the bathroom itself. There were also a couple of loose tiles around the base of the shower cubicle which needed to be re-fixed.
Cleaning Ceramic Tile and Grout
We started by spraying the tile and grout down with Tile Doctor Pro-Clean which is a strong alkaline cleaner, spraying it on mixes it air which helps it to stick to Vertical surfaces allowing it to get to work on the dirt. We left it to dwell for ten minutes before scrubbing it in by hand using a stiff grout brush; this process certainly improved the grout but unfortunately it had become too badly stained to be satisfactory so we decided to recolour the grout using a white grout colourant.
Once the shower tile was dry the loose tiles were removed and the damp plaster board behind chopped out and replaced. The tiles were then cleaned up, fixed back into position, then grouted and the silicone sealant around the base of the shower cubicle was stripped out and replaced with new.
One to two coats of white colourant were applied to the grout throughout the shower cubicle and shower room in order to get a uniform appearance and this final touch completed the transformation.
The other advantage of these particular colourant products is that they are epoxy based and form a barrier of the grout preventing future staining and making it very easy to clean going forward.
Source: Restoring the Appearance of Shower Cubicles in South Cumbria