An extractor or a dehumidifier or good airflow which includes the window plus another point of entry would do.
How to dry out wall behind tiles.
If plaster board is behind tiles then this should be removed and replaced with cement board which will not absorb moisture like plaster board.
Step 2 place a wide putty knife under the ceramic tile parallel to the floor.
I am running a fan for a few more days to try to dry out behind the tile.
A fan inside the cube will dry the water out of the wall.
If they are solid walls then allowed to dry out and once dried sealed with sbr primer ready for re tiling.
Let the wall dry thoroughly.
Not sure how long it will take to dry the wall out any.
Tap a rubber mallet on the head of a small chisel to remove the grout in the tile joints.
Let the grout dry.
The source of the damp is definately the tiles themselves we havent been here too long and when we looked some of them they are mosiac tiles were virtually falling out where the bath joins the wall and just n the spot where the shower falls onto them.
You then need to remove the damp air.
Hold the float at a 45 degree angle to the wall to push the grout into the joints between the tiles.
Seal the walls with a skim coat and let it dry thoroughly.
All tiles need to be removed from shower area walls inspected for moisture penetration mould.
Start by removing any molding switch plates outlet covers and other hardware attached to the area being tiled.
Turn the float to 90 degrees to remove the excess grout from the tile faces.
The tile is 12 floor tile w inlay tiles.
Its quite an old flat c1900.
Scrape away any loose or peeling paint or wallpaper.
Thoroughly vacuum the area and give the wall a once over with a damp sponge or cleaning cloth.
The corners have little grout after removing the caulk they have up to 1 8 gaps up to the top of the shower.
Use the rubber mallet to tap the head of the putty knife to pop the ceramic tile from its place.
Remove any remaining dust oil or grease with tsp tri sodium phosphate or an ammonia based cleanser.