Surface damp on floating chipboard floor

[Jasmine99]

Hello, everyone!

I have a strange problem with my floor. I recently took up my carpets to find some distinct and separate patches of damp on the floor. Thinking it was being caused by a burst pipe, I called a plumber who cut a piece out of the floor only to find no accessible pipes, nor sign of any damp whatsoever on either the polystyrene insulation layer or the DPM. More bizarrely, there is no sign of damp or staining on the underside of the damp piece of flooring. The damp is superficial and there is no mould growth.

The damp patches are drying out before reappearing. No direct correlation between the reappearance of the patches and either use of domestic water or rainfall is immediately evident.

I have no idea who to call on for help! Anyone got any ideas? Photos attached!

The damp does not extend to the adjoining room beyond the skirting, and the two patches to the right of the picture are beneath a bed, being about two feet apart.

The property is a late 80s built ground floor flat.

 

[foxhole]

Looks like historic spill damage , looks to be dry?

 

[Jasmine99]

Hi, and thanks for your reply.

As I said, the patches dry out before reappearing. They dry really quickly as the damp is so superficial. If I didn’t know better, I would swear a cat was coming in and leaving several liquid deposits - although how it would pee under the bed is anyone’s guess!

 

[Jasmine99]

Well, the mystery deepens!

We took the cut our piece of floor and placed it flat elsewhere, so we could look for signs of water after any rain. Everything remained dry for a week…until this morning. The piece of flooring was once again becoming damp, in the place it had been left after being taken up.

We had previously drawn around the damp patch to monitor any spread, but the damp never went beyond the line. This was again the case today.

Please, please can somebody come up with a (sensible) suggestion as to what is happening? Am I dealing with the ghost of somebody who had been drowned and has come back to wreak its terrible revenge?

Here is a photo of the emerging patch this morning. It is now up to the lines!