Random question about damp and water - any experts out there?

[FreckledLeopard]

So, having had a load of building work done recently on a Victorian terrace, and having had the joy of trying to source where water was penetrating into the walls, I have been musing about the sources of damp (yes - I lead an exciting life).

Anyway, I'm currently having the back of my house re-rendered (to hopefully stop water coming through cracks) but I was thinking about sure-fire ways to find the exact cause of damp.

Does anyone knowledgeable know whether there are devices that can be used to literally pinpoint water coming into a building? For example, like some kind of infra-red or X-ray device which will pick up the presence of liquid in a house? So you could almost 'scan' a wall and it would pinpoint where water was entering the building (cracked rendering, bodged windowsills with cracks in, rising damp)?

As I say - odd question - but am very curious to know the answer.

[Chewedover]

Freckled, you need a damp detector/moisture meter. There are various models - should be able to pick one up for £10 - £20. (Actually, I think I might need one myself).

[Trumpton]

We are having the same problem and we know we have damp but where it is appearing ( pouring in ) is not necessarily anywhere near the point of entry.
We are now thinking of having the whole of the back of the house stripped of the old render and then re-rendered and the 20 windows taken out cavity trays reset whilst the brickwork is exposed. We have had rain getting in for ten years now !

[FreckledLeopard]

The thing is, I know where there is damp, I just don't know the exact source of it (i.e. from what point water is entering the external wall and the route it's taking through the wall until it ends up causing damp internally). Are there any machines out there which will provide a visual aid as to water sources?