Water marks inside on downstairs chimney breast

[D__Q]

Hi there,

Recently I noticed that there are some water marks on the paintwork of one of the downstairs chimney breasts in my end of terrace house. Both breasts face the pathway on the outside of the house, i.e. not adjoined to the neighbouring property. Note that there's no issues on the breast in the bedroom above where the same breast is located (there's also no chimney vent on the breast in the bedroom)

Moved in end of November, house was empty for a few months beforehand. I don't recall seeing it these at the time, but I did have boxes, etc. stacked up in front of it for a few weeks (realised I needed to move them so the chimney could breathe) and I think it's been since then that these water marks have appeared

Believe that the previous owners blocked up the chimneys and there's a vent present. When it's windy I hear the wind whooshing down the vent.

Wondering if this is just condensation - finding it hard to believe that rain is making it all the way down the chimney breast and only showing downstairs.

There's no funky smell or anything and nothing odd around the skirting - the carpet around the area in the second picture is slightly crunchy/seems as if some plastic is scrunching a bit underneath - I don't have the tools/knowhow to be able to lift the carpet to investigate further.

Any ideas what could be causing it, and what I should do or who I should call to look at it?

 

[motorbiking]

Do you have a cowling over the chimney? It might be rain blowing down the stack. Upstairs and downstairs will usually have different routes, so one not leaking isn't relating to the other leaking.

 

[D__Q]

No the pots aren't capped off at all

 

[JohnD]

Do you drape wet washing in the house?

Is it a concrete floor?

Is the carpet damp between the radiator pipe and that wet patch?

Stand back and take a wider pic to show the whole wall, floor to ceiling please

 

[D__Q]

The washing dries in the small room upstairs, with a dehumidifier turned on as well.

Don't believe it's concrete floor, pretty sure it's all floorboards, then underlay, then carpet

The carpet is not damp between the radiator pipe and the water mark

Floor to celling pics as requested are attached (though not overly clear)

 

[motorbiking]

Take the vent off and have a look inside for water evidence.

 

[D__Q]

Hi there, yep took it off and there's only a small opening - can just about fit my hand in the hole and up slightly. Doesn't feel wet inside (just dirty & grubby as you'd expect). It hasn't rained in a while where I am either

 

[motorbiking]

can you get an iPhone camera in there with a light.

 

[D__Q]

Here's a video showing the inside of the chimney breast

 

[motorbiking]

Does the chimney run up to the left at an angle? That seems to align with the wet patch. The bottom seems dry, but I wonder if the water is running down to the point it angles.

 

[D__Q]

Yeah could be, so you think it's water coming all the way down from the chimney pot? What about the mark on the front of the breast in the first picture?

 

[motorbiking]

alternative options could be an overflowing guttering, or a leaking radiator pipe upstairs. What does the ceiling look like?

 

[D__Q]

Ceiling is fine, pretty sure there's no guttering on that external facing wall on the downward slope of the roof