Kampa prefab house from 1978 - but musty smell.

So, there is news.

On the weekend, I drilled a 15mm hole into every wall in the mustiest room (through the drywall and through the V100 board inside up to the insulation). Absolutely NO smell is detectable from these holes! I also put the drilled-out chipboard pieces into a glass with a lid to collect the smell. A smell is perceptible from this, but in my opinion, it is different from the one present in the room.

Then I went back under the roof. There you actually don’t smell anything, BUT the roof is also not insulated upwards and well ventilated, so that makes sense. From the side, you can also reach the walls there, which also don’t smell.

Now for the news. Above the stinky room, I found a lot of mouse traces in the insulation. Unfortunately, everything was there, from urine traces to droppings to nests.
What do you think, could it also be because of that? Assigning the smell to the rooms is really difficult for me, but all other rooms are definitely odor-free! Only 2 rooms are really affected, both are on the north side and are only interrupted by the tiled and thus denser bathroom. And the entire north side has mouse traces. No traces were found on the south side.

Mice stink - that's a fact. Former nests also stink, even if the mice have long been exterminated. Go to a pet store and smell the mouse enclosure. Then you'll know if the smell is similar. The first question is probably: Could there still be some in the house and above all - how do they get in?

There are definitely still some around! I saw a shrew and have already caught one in the trap. I just hope they are only mice and not also the bigger friends (rats).

Where they get in... ventilated brick facade. I think hardly anything can be changed about that.

Well then, you have your answer. The mice must be fought. We also had that once in our old house. After that, my dad really sprayed the entire basement and all the walls up to the top of the roof with construction foam in any holes where even a sheet of paper could fit through. It helped - but it was time-consuming.

Hello,
better get an exterminator quickly.

Friends also once had a mouse problem, at first they tried to handle it on their own, but there were more instead of fewer.

And check your building insurance, some insurers pay the exterminator costs in case of acute pest infestation.

The exterminator also finds the place where they come in and can make suggestions on what can be done about it.

Best regards
Birgit

There is news, and I ask for further opinions on the changes:

1. Structure of the house:
Walls from outside to inside: clinker brick, air gap, V100G, mineral wool between wooden studs, V100, drywall.
Ceiling: from the room upwards to the roof: drywall, V100G, mineral wool, and unfortunately partially V20 on top to walk on.

2. Investigations:
Roof truss:
The mouse droppings and the mice are mostly removed. Noticeably fresher air under the roof. (I will completely replace the insulation).
I put a piece of chipboard into a glass with a lid there. Even after days it only smells like chipboard, not as musty sweet as the room.
What is striking, however, is that the insulation is black in many places. No smell can be detected at these spots. Since it is mainly outside, I assume dirt is being moved by the wind between the clinker brick and chipboard?
Walls:
In the stinking room, I opened an outlet on an exterior wall and an interior wall (interior drywall, V100, insulation, V100, drywall), took the box out and also broke off some chipboard and put it into a glass. No smell was detected. The insulation behind it is only yellow and odorless.
Floor:
The two rooms with odor still had old laminate installed, which was laid directly on the old carpet adhesive residues without a vapor barrier and without impact sound insulation. This has now been removed. The laminate definitely smelled! Whether the odor came from it is hard to say, since now the old adhesive smells a bit. I will sand it down in the coming days and observe the odor.
What is certain here, though, is that the room significantly lost odor the emptier it became! Of course, the room volume also increased and the odor substances could disperse more.

3. Confusion.
I have no idea anymore... Money is tight since the house was only recently purchased and renovated. During the renovation, we had some parts of the drywall (guest WC was bare because of pipes etc.) open. The guest WC is right next to the most stinking room, and absolutely no odor came from the wall there.
An indoor air investigation is planned, I just don't know where (Nuremberg area). Because simply spending 2k€ is quite steep after the whole renovation.

4. Gratitude!
I would not have thought that both here and specialists would help so much!
What I would still like is contact with someone who has successfully renovated a similar problem and its chipboard bunker without further odor! Unfortunately, nothing can be found about this.

Best regards and have a nice weekend everyone.