Is the wall falling apart?

[AJ82]

You say it's an interior wall? If that's really the case, is there another room behind the concrete?
If so, it's quite odd with that degree of moisture. It's hard to imagine that so much can be drawn up from the bottom plate. Are you sure it's not, for example, a pipe leak that's causing the moisture?

Yes, on the other side is the laundry room. However, one end of the wall ends in an exterior wall.

 

[Carl Johansson]

You can cover that with a softer mortar, perhaps a kc-bruk or c-bruk.

 

[Henningelvis]

Yes, on the other side is the laundry room. However, one end of the wall ends in an outer wall.

Might be worth checking how the other side of the wall looks and also the piping in the laundry room. Do you possibly have a small leak in the water or sewage? A long shot could be that you have high humidity and poor ventilation in the laundry room. Drying cabinet or dryer that is used often and pushes out warm, humid air? I'm quite nervous when it comes to moisture and would have liked to rule out that type of impact.

 

[Stefan1972]

You need to distinguish between drainage and protecting the facade from penetrating ground moisture.

Drainage:
Aims to keep the water level low so that water doesn't stay above the footing of the basement. This prevents moisture from rising or being absorbed through the slab or through the walls in the basement.

Facade protection:
Water from above (rain/roof water/snow) that finds its way into the ground to the drainage can instead enter the facade. Then the facade needs to be protected. Previously, cold asphalt was applied to basement walls, which made it difficult for moisture to enter. The asphalt has a best-before date as it gets worse and worse and the protective function decreases. Newer solutions are Platon mats (there are other brands) and insulation boards that are installed to prevent moisture from hitting the facade and instead finding its way directly to the drainage.

So if previous owners have done drainage, it does not mean that the basement is protected from penetrating water. To prevent the basement from getting worse, the exterior also needs to be reviewed!

Inside, it is undoubtedly good to remove the organic material to air and dry the wall.

but it doesn't quite work that way with drainage either.......drainage in itself cannot maintain any water level below a slab. An old house without a capillary-breaking layer under the slab may still have ground moisture upwards no matter how much and how good the drainage is. No drainage can cope with those forces.

 

[ettan47]

It also depends on what kind of foundation you have in the basement. If it is a solid concrete slab, it should be fine when you have removed the paneling and studs on the interior wall and allow it to dry out, provided the drainage is properly done.

If you have an old house, it is rarely a solid concrete slab; in this case, both the exterior and interior walls stand on their own foundations against the ground, and between the exterior and interior walls, the basement floors were often cast directly on packed sand. In older houses, a capillary-breaking material is often missing under the floors and interior walls that stand directly on sand or earth, and then the drainage only works for the exterior walls. If the interior walls do not dry out even though you remove the paneling and studs and have new functioning drainage, I believe the reason is the absence of capillary-breaking material under the interior walls and basement floors. You can solve this in different ways. One option is to install a Platon mat on the walls and floor, and then frame the floor and walls with metal studs to solve the problem. Another option is to open up a part of the basement floor where you have the most issues and create a deeper "well" so that the majority of the water finds its way there; here, you should install a drainage pump with a level sensor to lead the water out.

Then my last advice is to NEVER install underfloor heating in an old basement, as it will increase the capillary action even more. If you have underfloor heating installed, turn it off. To install underfloor heating in a basement of an old house and have it function, you need to remove the floors, add new capillary-breaking material, and plenty of ground insulation.

 

[Plupp 168520]

but it doesn't really work that way with drainage either.......drainage in itself can't keep a water level below a slab. An old house without a capillary breaking layer under the slab might have ground moisture rising no matter how much and how good the drainage is. No drainage can handle those forces.

You are absolutely right, and there are probably 100 other details that neither you nor I wrote down. That doesn't mean what you or I wrote is incorrect, it's just not complete information.

The purpose of what I wrote was to explain the difference between drainage and protection from water intrusion from above in relation to the original poster's earlier statement that drainage was done.

I'm not alone in thinking it looks strange with plaster detachment so high up on the wall. The original poster also mentions that one side of the interior wall faces the exterior wall.

@ettan47's post explains more thoroughly how it can be if there is poor/lack of capillary-breaking material and what can be done about it. Well written!

Now the interior wall can be heated, and the temperature difference can affect the capillary effect, or as @Henningelvis wrote, a water damage might have caused it.

There are simply a lot of question marks and possibilities...

It would be possible to break up a hole in the concrete floor when the wooden floor is gone to see what material is underneath and if it is wet.

Based on what has come up, I would start by tearing away the organic material and then wait a few months to see if it becomes more humid again or if it has dried up completely. After that, decide on how the wall should be addressed.

 

[AJ82]

Might be a good idea to check how the other side of the wall looks and also the plumbing in the laundry room. Do you perhaps have a small leak in the water or drainage system? A long shot might be that you have high humidity and poor ventilation in the laundry room. Dryer or tumble dryer used often, pushing out warm, moist air? I'm quite nervous about moisture and would like to rule out that type of impact.

This is how the other side of the wall looks (as much as you can see through my partner’s collection of pots/jars):

White and smooth it is at least. There are some bubbles in the paint in a few places, but I also don’t know what type of paint was used when the wall was painted.

Furthermore, maybe I should clarify one thing: The studs were really wet, so you could crumble them with your fingers, at the bottom against the wall, but higher up on the wall they were in good condition. At the height where the wall is at its worst, I don’t think it’s obviously damp, but feels more like dry sand.

Moisture is a chapter in itself that I need to address, but right now I’m mostly worried about whether there’s a risk of more of the wall collapsing and what risks that entails. I think (but I'm not sure at all) that there might be a steel beam resting on top of the wall, running lengthwise. On the other side of the house, in the garage, there's a fully visible steel beam extending towards the extension of this wall.

 

[AJ82]

The laundry room is ventilated with continuous mechanical exhaust. We have only lived in the house since around midsummer and have dried all the laundry outdoors without using a dryer. Before we moved in, the house was empty for about a year, so I can't imagine it has been particularly humid in the laundry room, at least not recently.

A water leak cannot be ruled out, I suppose, but it seems unlikely based on what I know about the water and sewer pipes.

In any case, I have contacted a construction company that will come and take a look next week. Hopefully, the house will still be standing then