Am looking for some advice (and possibly peace of mind?) about some damp plaster in my airing cupboard and bathroom.
Returned from holiday earlier this week to find a leak from our cold water storage tank overflow pipe (the ball cock wasn't closing off properly). Plumber came out and replaced the ball cock, so no more leak. However the water stains, which run all around the airing cupboard from ground level to about a foot/foot-and-a-half up, don't seem to be drying very much (if at all), despite having a dehumidifier going and the heating on (albeit the latter isn't 24/7).
There is also a large damp patch at the head of the bath (the bathroom is beside the airing cupboard), from ground to about a foot up. Not sure whether that'd been there from the start or is more recent. There are small bubbles appearing in the paintwork on a wall in the hall in the last day or so. This wall is the other side of the damp wall in the bathroom.
The floor of the airing cupboard is still quite wet, but below the bath is bone dry. Our pipes are handily buried in a concrete floor, which is a clever design feature until they leak.
In several places there are white powdery deposits appearing on the wall; I don't know what these are - some type of mould? Salt?
I suppose my questions are as follows:
Is it likely that there is another leak, or is the water that came off the overflow pipe and leaked into the airing cupboard just spreading out?
Assuming the latter, how long should I expect it to take for the plaster to dry? Is there anything I can do to speed up this process?
At what stage do I get a plumber back and have him start tearing up the concrete floor looking for leaks?
I live in a first floor flat; to date, the downstairs neighbours haven't come charging round complaining of water leaking through their ceiling, which is what i would expect were one of the buried pipes leaking.
Grateful for any advice. I can post pictures if that would help, particularly around the layout of the flat.