Random damp patches on wall

[DIY67]

I have a spare room with a cold outside wall that has always had condensation hence drips of water. I have hung insulation lining paper with Warlock thermal paste to the left side of the chimney breast. The wall is much warmer. So far so good. I am about to hang it on this side of the chimney breast but there are random damp patches I can't fathom as it isn't condensation (no water run marks). Even stranger are the damp patches on the chimney breast itself which has a gap between it and the outside wall. In fact, the downstairs fire is being used so there is warm air between. The chimney itself was pointed 2 years ago, as well as a new roof. No leaks at all there. and I have storm dried about halfway up the outside of that wall (I need to get higher with some scaffolding to finish) I have also invested in a dehumidifier. I can open the window as much as I can but not in cold weather as I* will lose heat.

So apart from not knowing what is causing these patches, I am hoping that covering the wall with the insulation paper will stop it. I shall try and get higher up (perhaps extended paint roller up a ladder) to finish the storm dry as soon as we get a couple of rain free days as I suspect the odd spayed bricks may be the culprit. The house was built in 1883.

 

[foxhole]

Damp on and around chimney breast is usually down to unventilated and or uncapped chimney pots .
The fireplace would normally keep the area dry as it heats and causes very high levels of ventilation .
Remove the heat source without capping the chimney to reduce rain ingress and adding ventilation result in damp.

 

[opps]

It might be hygroscopic salts in the chimney breast itself. They absorb moisture in the warm months and when it becomes cold and damp, they dump them through the neighbouring brick work.

Take a photo from further away (showing the chimney breast as well).

 

[DIY67]

I have covered the recessed walls with the lini8ng paper and it has made a huge difference. The walls and room are no longer cold. Just can't fathom why the chimney breast which has a cavity behind it has damp. I was going to leave the chimney breast and paper with normal lining paper using thermal paste instead of standard wallpaper paste ?

 

[opps]

I have covered the recessed walls with the lini8ng paper and it has made a huge difference. The walls and room are no longer cold. Just can't fathom why the chimney breast which has a cavity behind it has damp. I was going to leave the chimney breast and paper with normal lining paper using thermal paste instead of standard wallpaper paste ?

Erm... perhaps Google "hygroscopic salts".

I am a decorator, I have come across similar problems. If it is down to the salts, by the end of the year, you may see damp patches appear through the lining paper.

The chimney is likely to be full of old soot- that soot absorbs moisture and in the colder months it dumps the moisture through the existing plaster- and lining paper... I am not making this up.

 

[DIY67]

I have noticed Jackdaws nesting for the first time in our chimney but there are two pots, one for the current open fire downstairs and the other for upstairs (the studio room in question which used to have an open fire) They have nested in the unused pot.

I can see that the salts may come through the normal lining paper but I very much doubt they will come through the polysyerine backed insulation paper. They dont just appear on the chimney, they are also on the walls, near the top of the ceiling which are nothing to do with soot.

23 years ago I had some old wardrobe doors dipped and stripped to the original wood. to this day they still attract wet patches on the wood despite taking off and drying in the summer sun. I have even jet washed the doors to flush out any remaining chemicals used for stripping. all to no avail. my only option is to perhaps wax them.