Significantly high humidity in the cellar

Hello everyone,

In the house we bought just over a year ago (built in 1990), I am currently having major problems with high humidity in the basement. I measured the values with a hygrometer and they are around 83%. The rooms also smell musty and moldy. The light wells to the basement windows are also damp and moldy, with humidity around 88%, and the stones in them are even covered with green moss (or whatever that is?). However, this is not the case for all light wells around the house.

Since our previous owners state they did not have such problems, I believe we caused the problem ourselves through incorrect ventilation. Because a musty smell quickly spread in the basement after we moved in, I tried to keep the windows open as often as possible, even in the summer. Now I have done some research and read that in summer the basement should only be aired at night, as it is more humid outside during the day.

Now I have some pressing questions about my situation:

What measures can I take to speed up the reduction of humidity? The windows are now closed during the day. Does it help to set up a fan at night that pushes the moist air outside? How can I prevent the wooden paneling and furniture in the basement (there is no wallpaper) from starting to mold? Are there ways to dry out the light wells of the windows? What influence does the sauna have on the humidity? Generally, the sauna is a very dry heat, but every 2-3 weeks about half a liter of infusion fluid is vaporized inside, which then escapes into the room air.

In addition, there is the problem that the storage room (open clay floor with sandstone) became wet from below due to the flooding in the Württemberg area. This room has only a small window, which has been open continuously since then. Also, a fan was installed by a company for over a month, which ran continuously during that time. Relatively soon after the floor got wet, mold began to grow. This was then removed by the company, but now the mold has spread to the wooden shelf in that room.

The question here is how should we proceed further in this room? The shelf has to go, that is clear. But how can we get rid of the mold spores that are obviously floating around here? After all, our food is supposed to be stored in this room. Should we set up a fan? Is it better to keep the door open or closed?

I know I have probably overwhelmed you with my problem, but I hope you can still help me with some points. The situation is really stressing me out.

I would be very happy to receive answers!

Best regards, Markus

As it sounds, I would set up an electric dehumidifier. It can be adjusted to the desired humidity level and switches off once this is reached.

Regards

Also believe that Blockhauspoers proposal is a good solution. The problem is just that the basement is too "cold" for the soup air.

Here it is about 25 degrees outside and 70% humidity, if there is some drizzle even more. When this air cools down in the basement you quickly reach 90%. So only a dehumidifier/dryer helps and otherwise in such weather keep the windows closed.

from on the road

Hello,

thank you very much for the tips, the issue should be clear regarding the matching posts. I need a dehumidifier.

The only question is how I approach the topic now. Is it better to buy a smaller device that I then alternate between the rooms or a larger one that is centrally placed in the basement hallway and dehumidifies all rooms at the same time?

The problem with the second solution will be that the staircase to the ground floor is open at the top and there are only doors in the entrance area that can be closed. This significantly increases the volume that the dehumidifier has to handle.

: Of course, I have already adjusted my profile.

Why buy? Rent a decent device to reach a basic moisture level. After that, just avoid intensive ventilation. That’s how I would do it. Continuous dehumidifying should not be the goal.