damp in cupboard under stairs

[python]

In a clients house there is a cupboard under the stairs. To the left is a wall with a chimney breats that is unused, no idea if it's capped off. There is a vent at the bottom of the chimney that is in the next room. The cupboard smells very damp, but on inspection the walls and imbers that make up the stair construction appear dry.

I lifted the carpet and there is some mould in the very corner of the cupboard, between the carpet and chipboard flooring.

Where is the damp coming from, and how do I rectify it?

I will talk through each picture in the next post once I see what order they are in.

[python]

1st pic - this is where the mould is. It's very minimal and is mostly on the underside of the carpet, although traces are visible on the chipboard.

2nd pic - Timber upright that bears stairs, external cavity wall in thermolits block, and poorly adhered skirting. This area looked not damp, but just bad, so here is where I lifted the carpet to inspect first.

3rd pic - Opposite side of internal wall. The left hand side of cupboard is the same wall as behind the shelves to the left of the chimney breast. As you can see, the damp does not appear to be directly adjacent to the breast.

4th pic - Overview of cupboard from the other side of the wall from pic 3.

[thescruff]

Condensation comes to mind.

What in the boxing, ? a water pipe ?

[python]

that's not boxing, it is a timber that bears the stairs.

[thescruff]

Unless something has been spilt (spelling please) then it must be from below, wet rot perhaps.

[python]

that's exactly what I said. Either something spilt or coming from below.

The wood isn't rotten in any way, and it seems unlikely that something would have beel spilt right back there in the corner in my opinion.

The thing is the floor is part of the rest of the house floor, so any rising damp can spread, I guess I have to take up the flooring?

Any chance it can still be condensation, even with no pipework?

[python]

musty-smell-under-the-stairs-t19240.html

this is another thread where a similar problem is diagnosed as caused by bad ventilation and an air brick in the back wall should solve it?

Now I don't know what to think

[thescruff]

Bad Ventilation and condensation are linked.

Have they hung wet coats in that corner, looking at the door maybe not.

I think the floor has to come up, or an exploratory hole.

[python]

they have recently bought the property, so no history.

[mikew1972]

What's above the cupboard? .....a bathroom?

[python]

stairs.

look to the right of the last pic, the stairs turn left and then left again.

[mikew1972]

OK, picture P1010654 (Small).JPG shows a corner with 2 walls. The one on the right is breeze block. What is the other side - Outside ...or kitchen ..kitchen sink? Also whats the other side of the one on the left?
Just trying to think laterally

Edit:
Sorry, just re-read the one on the left is chimney brest. The one on the right is?

[mikew1972]

If you remove the vent cover to the chimney after some wet weather can you get your hand through to feel around for dampness inside?

[python]

thermolite block is double skin external wall.

left wall is wall to the left of the chimney breast the other side.

right and above is stairs.

I am not in the house and won't be returning for a few days so cannot check the breast for damp right now, and may not be lucky to have wet weather to check when I am. But if you look at the chimney breast pic, those shelves to the left correspond with the back of the plastered wall in the cupboard. So the damp corner is at the corner of the shelved wall and the external wall to the left of it, not directly adjacent to the breast.

[mikew1972]

Gottcha so if the outside wall behind the breeze block is above ground level / damp course and there's no water dripping down inside the cavity from above its gotta be comming up through the ground ...unless the previous owners cat / dog liked to pee in that corner.