Unusually wet floors and carpeting in the bathroom after showers point to a probable leak in the shower tray. A steady leak will cause damage to floors and walls and can become extensive in a short amount of time. The longer the leak continues, the more expensive and intensive the fix will be. A little caulk now can save thousands of dollars later.
Locate the leak. Close off the shower drain with duct tape or clay and fill the shower tray with water. Use a bucket or garden hose to fill the tray so you can be sure that the source of the water is not from the shower itself. Fill the tray with water without spilling water over the side of the tray. Wait to spot the exact location of the leak. It may be possible to spot the leak immediately, but it could take an hour or more.
Drain the water and let the shower tray dry. Keep in mind the exact location of the leak.
Use a small utility knife to roughen up grout along the area that is leaking. Apply a sealant caulk over the grout and smooth with a finger or thumb along the groove. Follow drying times on the caulk packaging.
Block the shower drain again and refill the tray with water to the previous level. Leave water sitting for up to 24 hours.
Drain water immediately if there is an obvious leak. If it seems to be in the same place, apply a more liberal amount of caulk and let dry. Retest for leak.
For a nontiled shower tray, such as fibreglass, check the top seal for leaks. It is possible to have punctures or cracks in the floor of the tray. It will need to be replaced in this case.
Water damage can swell the wood in the walls and cause cracks to the tiles themselves. Check all tiles closely for damage and replace any that are chipped or cracked.