I got damp tiles on the floor in my bathroom. I also noticed rising damp on tiles fixed to a wall from exterior side of the bathroom.
I think it is a leaking pipe installed bellow the tiles but not 100% sure. As I remeber the pipe was installed somewhere close to the area where I see the damp so the leakage is likely to be true but....
From the other side of a coin just before the problem shows up we were cleaning the patio with a preasure cleaner and it was very extensive cleaning as we were preparing it for sealing/painting job. The patio is a cross of the bathroom wall and I belive high preasure pushed a lot of water in to the concrete below the tiles as they are not not well grouted, so this could be the other case.
To check posible pipe leak I have done simple test with a water meter like this:
1) Checked that all outside connection (shower, sinks, garden outputs) are not leaking. 2) Closed all outgoing water sources and took a picture of a meter at that stage. 3) Than, after 40 min I took another picture of the meter.
As you can see on the image bellow the gauge has moved sligtly in this 40 min. This would indicate water loss.
What further steps to take to make sure whats wrong?