Hello everyone,
I urgently need some advice.
We have a house that we bought in 2019 and partially renovated. All the windows are new with double glazing, and we installed underfloor heating.
In recent years, we have already experienced high indoor humidity levels, up to about 65% in winter.
This year, we even had high humidity of 55-65% in all rooms during the summer, and ventilating did not help. Now, in autumn, the humidity is rising above 70%, and we are gradually becoming unsure of what to do.
I measured the walls in all rooms with a moisture meter. The north-facing wall shows about 16% moisture in the corners. The interior walls have about 12%. However, there are no walls that are visibly wet. The roof and walls are also tight.
We regularly air the rooms by cross-ventilation, morning and evening, and now have a dehumidifier running in the bedroom. Still, mold is beginning to grow.
The north basement wall is also damp, but there is roofing felt between the stones, so I don’t think the moisture is rising from below.
Additionally, last year I insulated the basement corner with EPS insulation boards.
I believe I have covered all relevant details.
Does anyone have any idea what I might be doing wrong or where I should look next?
Best regards,
andre007
I urgently need some advice.
We have a house that we bought in 2019 and partially renovated. All the windows are new with double glazing, and we installed underfloor heating.
In recent years, we have already experienced high indoor humidity levels, up to about 65% in winter.
This year, we even had high humidity of 55-65% in all rooms during the summer, and ventilating did not help. Now, in autumn, the humidity is rising above 70%, and we are gradually becoming unsure of what to do.
I measured the walls in all rooms with a moisture meter. The north-facing wall shows about 16% moisture in the corners. The interior walls have about 12%. However, there are no walls that are visibly wet. The roof and walls are also tight.
We regularly air the rooms by cross-ventilation, morning and evening, and now have a dehumidifier running in the bedroom. Still, mold is beginning to grow.
The north basement wall is also damp, but there is roofing felt between the stones, so I don’t think the moisture is rising from below.
Additionally, last year I insulated the basement corner with EPS insulation boards.
I believe I have covered all relevant details.
Does anyone have any idea what I might be doing wrong or where I should look next?
Best regards,
andre007
WilderSueden schrieb:
I don’t understand the point of these leading questions. It has already been stated that manual ventilation is not sufficient with new windows—unless you consider ventilation a hobby. And if you install a ventilation system, it shouldn’t be limited to the bathroom but also include the living areas. Ventilation alone—whether manual or mechanical—will not solve the problem. Old building walls simply have poor insulation, and the dew point can only be avoided with very dry air. In the long term, external insulation is necessary. There are many more partially renovated old buildings with new windows but without ventilation systems or external insulation that do not experience problems, provided the occupants behave appropriately. Ventilation systems are a good thing if you want one and can afford it. But in reality, many do not want or do not implement them...
W
WilderSueden5 Nov 2023 12:33profil65 schrieb:
There are many more partly renovated old buildings (EFM) with new windows but without ventilation systems or external insulation, which do not cause problems if used properly.
Ventilation systems are a good thing if you want to have them and can afford them. But in reality, many people don’t want them or don’t install them... Of course, it is possible to manage without insulation and ventilation. To make the physics work, you simply heat to 23°C (73°F), air out 6 to 10 times a day to let the heat out, and have very dry air. This is definitely not a money-saving strategy, nor is it comfortable...
profil65 schrieb:
One more time, a question to the original poster (everyone else, please don’t give advice here 🙂)
Do you think that airing out once after showering and then leaving the house... is enough?
Do you think it helps to hang wet towels outside after showering and to quickly wipe wet shower surfaces with a squeegee?
Would you be willing to install a simple humidity-controlled electric bathroom fan?
Are you (are you all?) able to ventilate more frequently and for longer? I understand what you mean. I think a fan for all rooms would not be a bad idea, since you are not always at home.
I am trying to gather ideas here and prioritize them based on cost-effectiveness and benefits to plan a possible implementation.
X
xMisterDx5 Nov 2023 12:58Then all the houses from the 1960s would have to be rotting by now. Since that is not the case, there must be (still) other issues here.
A decentralized ventilation system never hurts?
We hadn’t opened the windows for three days, and even in the bedroom it was currently 22.5°C (72.5°F) and 57% relative humidity. In the living room, with 42%, the humidity was almost too low.
A decentralized ventilation system never hurts?
We hadn’t opened the windows for three days, and even in the bedroom it was currently 22.5°C (72.5°F) and 57% relative humidity. In the living room, with 42%, the humidity was almost too low.
profil65 schrieb:
I was also wondering why the previous owners chose a simple (thin) interior insulation. My guess is that there were reasons for it... However, the previous owners didn’t have the same level of airtightness as we do now. Before, you could see outside through the roller shutter box. If I put plastic on the wall, the wall will still stay cold, and moisture will condense between the wall and the polystyrene. (Screenshot)
As I see it, there are only the following options, right?
1. Install ventilation.
2. Use blown-in insulation.
3. Install climate boards on the north wall.
Exterior insulation is definitely much better, but I have to check whether the brick facade can support it. This means that in addition to insulation, I would need a new facade. The roof needs to be extended because otherwise the insulation would protrude. Estimated cost: 60,000-70,000.
Would it not be sufficient if the U-value is below 1, so that moisture does not condense on the window that has a value of 1?
andre007 schrieb:
I understand what you mean. I think having a single ventilation system for all rooms would be a good idea, since you’re not always at home.
I am trying to gather ideas here and prioritize them based on cost-effectiveness and practicality to plan a possible implementation. In partially renovated older buildings, airtightness can vary from very leaky to highly airtight. In many cases, a continuously running electric fan in the bathroom—controlled by time, humidity, or another method—is enough to solve problems, since the building allows sufficient air infiltration and the occupant behavior matches that.
I’m not a fan of one-size-fits-all solutions. It always depends on the individual case: what do I need, what do I want, and what can/want I afford? This basically applies to insulation and heating systems as well.
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