Water getting into cavity - no obvious signs

Dan-Dan

Hi All
Anyone experienced anything like this before, we have a pine end wall, SW Facing in West Wales, so we do get some weather down this way against this wall, see attached picture from recently you can see the blocks themselves, Roofer stuck as doesnt appear to be any issues in the loft, nor any cracked tiles up above, but looking at the picture, surely water is engressing into the cavity somehow to show itself like this? 
The issue doesnt show in the rooms below this one?
Anyone seen anything like this before?
Cheers

ic

I had water getting in above a window - only happened in particularly strong storms when the wind was coming from a different direction to the norm.  I used a hose and managed to trace it to a tiny 1/2 mm gap that had opened up a couple of courses above the window, two or three bricks wide.  I'd missed this when up the ladder and inspecting as it just wasn't obvious - basically the rain was being blown against the wall above, streaming down the wall and in the tiny gap.  I simply siliconed it as a quick fix, and since it hasn't happened again.  When the weather is better next year I'll scrape it out and remortar it properly.

Dan-Dan

Hi, thing is the cavity is designed to stop water making it to the inner leaf so somehow there must be ingress beyond the first leaf and the render

Jeepers_Creepers

Hi DD. This looks pretty evenly spread across that whole wall - is it?

If so, would any water coming down the cavity really spread out like this, or would it more likely form a localised damp patch? I'd have thought the latter.

I have seen someone post a pic of their bedroom wall where almost every block could be seen in dark outline. I think it was caused by warm, moist internal air finding the coldest bits to condense out on, and this happened to be the mortar lines - something like that.

 What's a pine wall? 

Dan-Dan

Hi JC

Its not the whole wall its probably a third of it in that area as per photo, it isnt there now, and only lasted a couple of days, but you can make out the bricks still on the paint, so as it wasnt the whole wall i think we assumed water engress somehow/from somewhere ?

Dan-Dan

Pine end, may be known as Gable end?

Jeepers_Creepers

Thanks.

And it only appears following particularly wet, wind-driven weather? Or does it also happen when it's just cold? 

stuart45

Looks like ghosting. Happens as Jeepers_Creepers said, when moisture hits the coldest spots in the wall. In this case the blockwork is colder than the joists. Sometimes the other way with AAC blocks.

Dan-Dan

joists   ?

Dan-Dan

Jeepers_Creepers said:

Thanks.

And it only appears following particularly wet, wind-driven weather? Or does it also happen when it's just cold? 

We have been here 4-5 years and this is the first time it happened, it has rained heavily recently and been cold but its never shown before this way

knightstyle

Buy or hire a dehumidifier and see if that stops it. It looks like cold area attracting warm damp air from inside the building.