Mystery Leak

We live in a village house and we have a leak. Normally that would not surprise me, however this one does and has flummoxed two pumbers already.

Facts:

1) The leak is from the ceiling of the top floor

2) A thin 1 meter crack in the ceiling leaks about 1 liter of water during about 2-3 hours and stops

3) The time it starts leaking is always around 1 in the afternoon

4) It leaks roughly on 1 day in 4, but no regularity.

5) The days it leaks do not depend on outside weather (I.e. it leaks when it is sunny or rainy or foggy)

6) There are no water pipes near the leak

7) The leaked water is clear and not salty

8) The leaking does not change due to use/non-use of bathrooms etc.


Up to now pumbers have suggested it is linked to use of bathrooms or a leak in the roof, however we have proven both are not the case.


I am really puzzeled and any suggestions/ thoughts really appreciated.


Thanks.

i am really no expert on this, but could the water condense from somewhere and be accumulating as such, only to be leaking at the highest temperature of the day (which probably is usually around 1pm)...


e.g. could it be steam from the shower that is supposedly piped out of the building but the pipe actually leaks into the walls/ceiling on the way out?


just a thought

Thanks for the suggestion, it certainly looks as though it is heat related. Another leak has just started in an adjacent room this afternoon...

to leak 1 liter in 2 or 3 hrs means it should drip like a leaky tap (or faster).


If you have inspected the top floor and it is dry, then then cause should be a leaking water/drainage pipe running along the ceiling. Im not a builder or plumber but I have lived in and seen enough village houses to know that pipes laid this way are very rare. Pipes routes are normally very simple, as you probably know all piping can usually be seen on the outside of the house attached to the side. If you see piping entering the building at ceiling level, then that is the cause.

Thanks, at the moment we thing it is probably water collecting under the tiles on the roof and when the sun shines the roof heats up allowing the water to come through cracks in the roof. We think the water may be collecting in some gulleys in the roof made for electricity to reach the roof top lighting. Anyway, cant do much until the rain clears up for a while....