Internal Damp

[jrb]

99% of internal damp issues are down to poor ventilation coupled with high humidity, so if you have any cold spots on the walls you will almost definitely get patches of damp. Cold spots can be down to many things, and one of the biggest culprits is poorly installed cavity insulation, and after that bridging between the inner wall and the outer wall. In older houses such as yours the gap between the inner and the outer wall is usually narrower than more modern houses, so bridging can often occur when you get mortar bridging the gap.

With an internal air temperature of 19 degrees and a relative humidity of 65%, any surfaces in your house that are 12.3 degrees (the dew point) or lower will form condensation. At 80% humidity that dew point rises to 15.5 degrees.

I appreciate the advice from everyone, thanks. But if you look back at the pictures you’ll see the damp is on the inner hallway wall, which has nothing to do with the living wall as such, even though it’s connected to it from the side. I’ll post a wider picture of the hallway later. There is plenty of ventilation in the hallway. The internal side kitchen wall that backs on to the living room wall is damp free. I checked that out recently when I replaced an old washing machine with a new washing machine. There was no damp there at all. You’d expect some damp on the kitchen wall as it backs on to the living wall, wouldn’t you? I really don’t understand why the damp is only visible along certain parts of the living wall and the hallway, whilst other parts of the same wall are damp free. Surely if there is damp it should be along the whole wall instead of just parts of the same wall?

A few years ago I filled the gap along the bottom of the plastered brickwork where the plaster ended above the floor. Then I put the skirting board on. I didn’t leave the gap between the bottom of the plastered wall and the floor. Do you think the moisture and damp is rising because I did that? I also stuffed paper into a visible gap on the corner of the wall to fill it, and then filled the gap. Just trying to think back to what I did when I took the gas fire out, which was no longer needed.

 

[Trevor Morley's Tache]

I appreciate the advice from everyone, thanks. But if you look back at the pictures you’ll see the damp is on the inner hall way wall, which has nothing to do with the living wall as such, even though it’s connected to it from the side. I’ll post a wider picture of the hall way later. There is plenty of ventilation in the hallway. The internal side kitchen wall that backs on to the living room wall is damp free. I checked that out recently when I replaced an old washing machine with a new washing machine. There was no damp there at all. You’d expect some damp on the kitchen wall as it backs on to the living wall, wouldn’t you? I really don’t understand why the damp is only visible along certain parts of the living wall and the hallway, whilst other parts of the same wall are damp free. Surely if there is damp it should be along the whole wall instead of just parts of the same wall?

A few years ago I fillEd the gap along the bottom of the plastered brickwork where the plaster ended and the floor. Then I put the skirting board on. I didn’t leave the gap between the bottom of the plastered wall and the floor. Do you think the moisture and damp is rising because I did that? I also stuffed paper into a visible gap on the corner of the wall to fill it, and then filled the gap. Just trying to think back what I did when I took the gas fire place out, which was no longer needed.

Older houses need to breathe. You can make them draught proof, but there needs to be a mechanism for the moisture to escape. A lot of moisture escapes through the walls, but if you've used a cement mortar, or used a no-breathable paint it will cause issues.

Have you done a humidity check? You can pick up a decent tester for around £20-30. Do a series of tests in every room, hallway and landing over a week or so at different times of the day/nigh to give you a decent idea of the trends. Anything beyond 65% is an issue and you need to takes steps to reduce it. Ideally below 50% average relative humidity is a good place to be and down to 40% if you can.

 

[Betterdeedthan red]

Only 3 ways you can get damp in a house.
Penetrating.
Rising .
Or a leak.
Think we can rule the 1st out as its an internal wall.
Rising can only rise to 1m high is it higher than that hard to tell of the pictures.
But in my experience if a damp course fails in a house it will fail all the way around not on certain walls.
So we're probably down to a leak.
Sounds like it's on the chimney area or close to it and work has been carried out on the chimney previously.
Check the stack and flashing would be my first job

 

[Coatigan]

99% of internal damp issues are down to poor ventilation coupled with high humidity, so if you have any cold spots on the walls you will almost definitely get patches of damp. Cold spots can be down to many things, and one of the biggest culprits is poorly installed cavity insulation, and after that bridging between the inner wall and the outer wall. In older houses such as yours the gap between the inner and the outer wall is usually narrower than more modern houses, so bridging can often occur when you get mortar bridging the gap.

With an internal air temperature of 19 degrees and a relative humidity of 65%, any surfaces in your house that are 12.3 degrees (the dew point) or lower will form condensation. At 80% humidity that dew point rises to 15.5 degrees.

You have just gone on to demomstrate that not 99% of damp issues is down to ventilation and humidity. By listing quite a few of a number of very different causes.

No amount of ventilation or dehumidifying is going to resolve damp caused by gradual water ingress. Which this could well be.

 

[Coatigan]

that would be one of the last things I'd do as it's not solving anything, also stop wasting money on paint as well until it's solved. Rule out the chimney first. Flashing, pointing, cap, damaged bricks, it could be any of these. Don't you have a drone? can you do a video of the chimney to see the state of the flashing? not sure if the video will be good enough but worth a try

I totally echo this. You are just wasting money with cheap fixes, and one way or another, thay **** is coming down eventually.

 

[Coatigan]

How much did that cost you? Obviously prices will have changed since then if it was a while again.

Cost my neighbour 2k to take a chimeny down and reroof over the area. 3 years earlier, they got a quote to do it for £1800. They spent £200 capping it instead. They then spent £700 releading and repointing it a year later. Then another year later, just took it down, by which point the cost had gone up. £1100 worse off and 3 years of annoyance later.

 

[jrb]

Once again, thanks for the advice.

Rather than going around in circles.

I need to get the chimney checked out.

Should I still remove the skirting board along the wall? The plaster is shot anyway, so the wall will need replastering. There isn’t much point in replastering over the shot plaster is there? That will have to come off, won’t it?

 

[Trevor Morley's Tache]

You have just gone on to demomstrate that not 99% of damp issues is down to ventilation and humidity. By listing quite a few of a number of very different causes.

No amount of ventilation or dehumidifying is going to resolve damp caused by gradual water ingress. Which this could well be.

The damp I've described is ultimately due to an elevated humidity, caused by excess moisture being produced with a lack of ventilation. The manifestation of the damp is ultimately due to a surface area being at or below the dew point which can happen due to the factors I've described.

It's why windows are often wet in the morning after the curtains have been closed overnight. Even if the room itself is relatively warm heavy curtains insulate the windows from the heat of the room, and as the surface of the glass cools to the dew point any excess moisture in the air condenses on the window pane.

Damp due to gradual water ingress is is entirely different, but adds to the overall humidity level within the property, exacerbating the problem.

 

[Coatigan]

The damp I've described is ultimately due to an elevated humidity, caused by excess moisture being produced with a lack of ventilation. The manifestation of the damp is ultimately due to a surface area being at or below the dew point which can happen due to the factors I've described.

It's why windows are often wet in the morning after the curtains have been closed overnight. Even if the room itself is relatively warm heavy curtains insulate the windows from the heat of the room, and as the surface of the glass cools to the dew point any excess moisture in the air condenses on the window pane.

Damp due to gradual water ingress is is entirely different, but adds to the overall humidity level within the property, exacerbating the problem.

Of course, we are probably talking slightly different purposes. I was more focused on interstitial damp, which jrb's photos look like, more than within the environment of his space or condensation based. I think it is a fabric issue myself, and has maybe hit a saturation point that was previously on the edge, mitigated by drying out quicker. But that's a very much at face value comment, at a fleeting glance at the photos. Prima Facie, I think the cool kids call it, ain't that right @halfcenturyup!

 

[halfcenturyup]

Of course, we are probably talking slightly different purposes. I was more focused on interstitial damp, which jrb's photos look like, more than within the environment of his space or condensation based. I think it is a fabric issue myself, and has maybe hit a saturation point that was previously on the edge, mitigated by drying out quicker. But that's a very much at face value comment, at a fleeting glance at the photos. Prima Facie, I think the cool kids call it, ain't that right @halfcenturyup!

Slay!