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.

Pictures: enter image description here enter image description here

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.

enter image description here Leaking toilet output could be a case as well.

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.

enter image description here I'm not sure how to read the gauge, what exactly is the loss and what it could mean.

What further steps to take to make sure whats wrong?

Thank you.

I'm adding an update with a third measurement following 5 hours after the send one. In my view they all show nearly 1 liter leaking a day. Could someone validate please? enter image description here

  • I believe that the moving dial shows 0.001 x cubic meters, which is liters. So, about a half liter of water was measured, which a) seems to match your symptoms, but b) could easily be some overlooked yet legitimate water use. Dec 23 '16 at 13:25
  • Are you sure? In my view 0.001 x is a liter but that would be a full turn of the pointer. Looking roughly pointer moved some 25% of the distance between 7 and 8. That would be about 25 ml in that 40 min. Given that figure it is 0.62 ml/ min or 37 ml/ per hour or 0.89 liter per day. Dec 24 '16 at 3:13
  • No, I'm not sure, although I'll bet it shows "m cubed" to the right of the digital display, in which case the meaning of the "x0.1", "x0.01" and "x0.001" dials are pretty clear. Dec 24 '16 at 3:45
  • Yes, It is m cubed for certain and if so, the dial "x0.001" is 1 liter. In such case how are you assuming the difference to be half liter? The pointer would have to move 5 units further. Whats more if that is half liter per 40 min, we would get some 10 liter leaking a day and that would make a way greater damage to walls and floors. That would be a pool of water not just slight damp. Dec 24 '16 at 6:17
  • 2
    No: the "x0.1" dial reads 0.1 through 0.9 cubic meters, the "x0.01" dial reads 0.01 through 0.09 cubic meters, and the "x0.001" dial reads 0.001 through 0.009 cubic meters, or 1 through 9 liters. In 40 minutes the dial went from about 7.2 to 7.7 liters; difference 1/2 liter, or 0.75 liters/hour. In 8 times as long, the dial went from about 7.7 liters to 9.9 liters; difference 2.2 liters, or 0.4 liters/hour. Pretty close. Dec 24 '16 at 13:16

There's no way to positively say whether it's the pipe or the pressure washer. The water meter readings may, or may not, be meaningful - that water could be going somewhere legitimate as Daniel Grissom said, and it's a very small amount of water. To check the pipe you'll have to get access to it, which means tearing up the tile. So what's more likely - a pipe started leaking at the same time that you pressure washed the patio, or that water got into the wall while you were pressure washing? If it was me, I'd get several fans blowing on the damp area for a few days to see if it drys up. If it makes no difference after a week, then maybe you need to dig into the tile.

  • Thanks for input Mark. I will respond to your answer tomorrow after proper waste measure is established as I think it does matter a lot.(Read my last response to Daniel's comment. Dec 24 '16 at 16:52
  • I have just tested the meter and it turns out Daniel is right. The smallest dial reads litters. In this case we see some 12-18 liters per day flowing through the meter.This is while all water outputs are closed. Does this not clearly mean serious pipe damage? The symptoms of rising damp appear some 3 days after using pressure washer. Dec 25 '16 at 6:01

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