QUESTIONI have damp grout in my upstairs tiled bathroom floor, but only in about a 2 foot area. it is about 2 feet away from the bathshower, so not near the waste pipe. There is no water seeping through when you stand on the affected area and no sign of any water leaking through the ceiling directly below. The wet area is not caused by using shower as the shower screen protects this space. The bathshower sits on normal wood floor boards, while the tiled floor sits on protected plastic water proof base. The tiled floor has been laid for about 2 years, and this problem has only just occurred in the last few weeks. hope you can help
ANSWERANSWER - Considering you are on an upper floor so water can't becoming in from the landscaping. And the spot is away from the shower and other water sources, but in the same room as the shower. If the moisture isn't coming from above the tile surface due to a spill or whatever, then it has to be coming from under the tile.
If the water is coming from under the tile and only showing up at one small area, then the source of the water must be coming from the shower or a sink where there is water. Leaks sometimes are not easy to find. They can show up in one spot, but the source can come from another area far away.
For one reason or the other water is traveling to this spot under the floor perhaps because it is a low spot of the floor. I would guess it is from the shower because if it was from a continuous water leak source it would be wet rather than damp. So possibly you have an intermittent leak coming from the shower or another water source. Try not using the shower for several days. Use a hair drying and see if you can dry out the damp grout. Then after it is dry see if the damp grout returns before you start using the shower. Then use the shower and see if it returns.
So if it is coming from the shower it may be a big problem trying to find out where it is leaking from. If it is the shower pan then it might be a major repair. If it is from the shower screen, then it might be an easier fix. Good luck.