Mystery wet patch

[WelshMoth]

Last October (just as DH buggered off to the Rygby World cup tour), a largish (square metre sized) damp patch appeared at the foot of the sofa DH always sits on. I cursed him for spilling something and scrubbed at the patch, dried it out, upended the sofa to wipe the mould that had appeared on the wipeable base and left it all to air. When talking to DH on the phone (he was away for 3 weeks), he denied spilling anything. I didn't believe him, but didn't pursue it.

We have a seagrass type carpet in that lounge, so it left a slight water mark. Carpet needs replacing eventually so I wasn't too bothered.

Fast forward to this week and the damp patch has appeared in the exact same place. DH insists that he hasn't spilled anything and I believe him. We've been camping last week and whilst away, the weather was shocking - lots of rain. The whole downstairs stinks of damp now.

The house is only 25 years old so surely, it wouldn't be a foundation problem?

We're totally baffled by the damp patch!

[whatsthecomingoverthehill]

Is it a suspended or ground bearing floor?

[WelshMoth]

Thanks @whatsthecomingoverthehill. It's ground bearing.

[wannabebump]

I'd suggest getting an inspection done from a property care company to include the foundations and damp proofing. I'm not sure how much a property age would affect what the problem could be as there are many other factors to consider (drainage, area, flood risk, other housing impact land, land beneath the house etc)

[whatsthecomingoverthehill]

Unless there are pipes in the floor that are leaking then I would guess ground water, and the DPM has failed. Pull the carpet back to see if it's obvious where the damp is from.

[averylongtimeago]

Several possibilities for this.
Water dripping from above should be easy to spot, so it's probably no that.
In a house that age, if the floor is concrete over a plastic membrane there could be ground water finding its way through a hole in the dmp.
Or are there any pipes under the floor? Concrete can react with copper to cause leaks, sometimes pipe fittings fail and leak.
Pull the carpet back and have a look, and try and work out the pipe runs.

[AdoreTheBeach]

We had something similar - twice. Different houses

One was that the shower/bath next door to a bedroom did not have the correct grout/seal in the new tiling. Water was leaking through the wall but we didn’t see it because of a free standing wardrobe. Water accumulated in the middle of the room and up the bed. I thought my daughter was constantly spilling drinks. It was g until mould developed sufficiently in the wardrobe and j moved it until we found out the wall had rotted and water was going into bedroom that way.

Second was house I’m in now. Water on floor. No windows around. No water on ceiling so not sure where it came from. Turns out when wind was from a certain direction and driving rain, water found a way in under roof tiles/between wall and roof and down a wall. Never saw any sign of this water though. No marks on the wall.

So have a good look around. Could be coming up from below or dripping down