spots/mould on the solid wall!

sujsuj

As you can see in the photo, there are some mould-like spots on the solid wall. This house is over 90 years old, and I haven't noticed any similar spots developing in the past four years. The entire wall in the upstairs bedroom seems to be affected. This wall is in the back of the property and has no wooden cladding, with all room separations made using solid walls as well. I will share an external picture shortly as well.

what should I look for as route cause? what solution..? If I ignore what will happen as this si solid wall!

Browntoa

Normally 3 main causes 

Lack of ventilation ( quite obvious, moisture inside on window glass ) can read moisture levels with cheap sensors.

Leak in guttering or roof causing damp on the wall

Failing damp course, so moisture is rising up the wall

Jellynailer

How long have the spots been there?  Have they got any worse over that time?  Is the room heated?  When was your guttering last cleared out? 

It is hard to respond usefully without the above information except to tell you about my experience of dealing with a damp spot problem = I had similar spots on the wall at the side of the first half of my stairs but a damp meter showed no damp so I put two coats of gloss paint on the wall and then emulsioned to match the rest.  It has been fine for over 10 yrs now.

stuart45

It could be a combination of penetrating damp and condensation. At that height I'd rule out rising damp. A solid 9 inch clay brick wall, with no protection like tile hanging or shiplap will allow moisture through the wall if there's enough driving rain. Once the wall is damp, it becomes a bit colder, so condensation is more likely to form on it. 
You can check the surface temperature of the wall with a surface thermometer.
If it's below the dew point, condensation will form. The
Internal insulation might be worth considering.

sujsuj

thanks. External photos are here. Problematic room is in first floor.

sujsuj

Browntoa said:

Normally 3 main causes 

Lack of ventilation ( quite obvious, moisture inside on window glass ) can read moisture levels with cheap sensors.

Leak in guttering or roof causing damp on the wall

Failing damp course, so moisture is rising up the wall

Yes there is a small gap and leak in guttering but that water is not falling on the wall. as  you can see that makes ground floor wall bit wet. Is that could cause damp in upper floor..? Thanks.

sujsuj

gutter gap

Lorian

It has been falling on that wall further up. Not only fix the gap and replace the seals on the gully you need to check guttering and downpipe are clear of moss. And do some pointing.

Not a job for someone not used to using a ladder.

Section62

Jellynailer said:

How long have the spots been there?  Have they got any worse over that time?  Is the room heated?  When was your guttering last cleared out? 

It is hard to respond usefully without the above information except to tell you about my experience of dealing with a damp spot problem = I had similar spots on the wall at the side of the first half of my stairs but a damp meter showed no damp so I put two coats of gloss paint on the wall and then emulsioned to match the rest.  It has been fine for over 10 yrs now.

Not a very good idea.

Gloss paint is likely to form a moisture/vapour barrier which may stop damp/vapour emerging from the wall causing staining, but it may also leave the moisture/vapour trapped in the plaster.  This may be fine, but could also result in premature failure of the plaster or, probably more likely, the gloss paint splitting/cracking/failing and leaving a mess on the wall to repair.

There are proprietary chemicals/paints that can be applied to achieve the same effect, but they need to be used with caution and awareness of how they work and whether they are suitable in each case.

The first step with damp is always to try to work out where it is coming from and attempt to cure it at source, not trying to paint over it as a first solution.

I'm sure it worked for you, but that doesn't mean it is a solution that would work for everyone.  Out of interest, how did you get the emulsion paint to adhere to the gloss underneath?

sujsuj, get your gutters repaired and make sure the downpipe is clear of debris and is free-flowing.  Then wait 6 months and see if you still have the problem inside.

FreeBear

sujsuj said:

Browntoa said:

Normally 3 main causes 

Lack of ventilation ( quite obvious, moisture inside on window glass ) can read moisture levels with cheap sensors.

Leak in guttering or roof causing damp on the wall

Failing damp course, so moisture is rising up the wall

Yes there is a small gap and leak in guttering but that water is not falling on the wall. as  you can see that makes ground floor wall bit wet. Is that could cause damp in upper floor..? Thanks.

The wall at the bottom looks to be absolutely sodden wet. The guttering and downpipe need looking at on both sides of the boundary. In addition, your neighbour needs to get some flashing on the "shed" roof or get rid of it completely. Not doing the wall any favours like that.

Jellynailer

Returning to the task of trying to help work out the nature of the OP's issue in the face of a range of opinions and speculation, I have no concerns about my own wall because my damp meter has recorded a 0 result for 10 years. A damp meter is not expensive and could be very helpful in this case.