Very high humidity in all rooms

Do you have radiators? Are they throttled or do you have it warm? Are they constantly on or do you skimp on the heat?

Hello everyone,

I urgently need advice.

We have a house that we bought in 2019 and partially modernized. New are all the windows with double glazing and the underfloor heating.

In recent years, we have already had high humidity of up to about 65% in winter.

This year, we already had high humidity of 55-65% in all rooms in summer, unfortunately airing did not help. Now in autumn, the humidity rises to over 70% and we are slowly at a loss.

I measured the walls in all rooms with a moisture meter. The north wall is about 16% moist in the corners. The inner walls about 12%. But there are no walls that are really wet. The roof and walls are also tight.

We regularly air the rooms intensively, morning and evening, and meanwhile have a dehumidifier in the bedroom. Nevertheless, the mold starts to grow.

The northern basement wall is also moist, but there is roofing felt between the stones, so I don’t think it rises from below.

In addition, I insulated the basement corner with EPS last year.

I think I have covered everything.

Does anyone have an idea what I am doing wrong and where I can look.

Regards, Andre

Have you also renovated the walls? The information is a bit slow coming for such a compact topic.

Where exactly do the mold spots appear? On the north wall? Is it in the bedroom? Do you heat there continuously? Are the room doors often open?

We had the same problem after renovation in an old building (double-glazed windows, new radiators), but in the living room (mold on the west wall). The problem was solved with thermal insulation.