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Pluto197720 Nov 2019 16:18Hi,
I need some advice. In our house (3 years old, solid construction, 36.5cm (14 inches) Poroton blocks), there is mold forming in one room at the corner where two walls (both exterior walls) and the ceiling (upper floor under the flat roof) meet. There is no mold anywhere else in the house, and we ventilate the room daily.
I had the roofer check the site, and they removed the roof down to the concrete layer, but everything is dry there.
Now we’re really stuck... Everyone is puzzled. What could be causing this problem?
Thank you and best regards
I need some advice. In our house (3 years old, solid construction, 36.5cm (14 inches) Poroton blocks), there is mold forming in one room at the corner where two walls (both exterior walls) and the ceiling (upper floor under the flat roof) meet. There is no mold anywhere else in the house, and we ventilate the room daily.
I had the roofer check the site, and they removed the roof down to the concrete layer, but everything is dry there.
Now we’re really stuck... Everyone is puzzled. What could be causing this problem?
Thank you and best regards
H
hampshire20 Nov 2019 16:25Moisture can come from the inside if the corner is "cold" for any reason. Measure the temperatures on the walls.
Heating and ventilation... this should solve the problem.
Daily ventilation can mean many different things, and even with daily ventilation, mold can develop if heating is insufficient and/or there is not enough air exchange.
Moisture in these cases usually comes from inside, mainly from people, pets (simply being present is enough), and plants. Exterior walls are colder than the rest → condensation → mold.
Adequate heating + ventilation = no cold walls = no condensation = no mold.
Daily ventilation can mean many different things, and even with daily ventilation, mold can develop if heating is insufficient and/or there is not enough air exchange.
Moisture in these cases usually comes from inside, mainly from people, pets (simply being present is enough), and plants. Exterior walls are colder than the rest → condensation → mold.
Adequate heating + ventilation = no cold walls = no condensation = no mold.
This is easy to clarify. I assume there is a thermal bridge. Use a laser thermometer to measure the spots where mold appears. It is important to do this when the outdoor temperature is below 5°C (41°F), preferably even colder.
Then measure at another spot where there is no mold to have a reference value.
You can determine humidity and room temperature with a standard measuring device costing around 20 euros. Then you can calculate the dew point; if it is exceeded, mold will occur.
The solution can be to heat more and ventilate properly, or to insulate the affected areas from the outside, if possible. Alternatively, insulation from the inside can also be done.
Then measure at another spot where there is no mold to have a reference value.
You can determine humidity and room temperature with a standard measuring device costing around 20 euros. Then you can calculate the dew point; if it is exceeded, mold will occur.
The solution can be to heat more and ventilate properly, or to insulate the affected areas from the outside, if possible. Alternatively, insulation from the inside can also be done.
P
Pluto197720 Nov 2019 19:34Hi,
thank you very much for your answers. Regarding the questions:
1. There is no furniture there.
2. I just measured the temperature on the wall. It is 2 degrees Celsius (3.6°F) colder (17.2°C (63°F) compared to 19.3°C (66.7°F)) than in other areas. I wonder how a thermal bridge could form there, but I’m not an expert.
3. The humidity level just shocked me: 67%. It’s a "baby room" that is actually only used by a child at night (now no longer because of mold). So I’m wondering where the moisture is coming from. I’m thinking about getting a dehumidifier—what do you think?
Best regards and many thanks
thank you very much for your answers. Regarding the questions:
1. There is no furniture there.
2. I just measured the temperature on the wall. It is 2 degrees Celsius (3.6°F) colder (17.2°C (63°F) compared to 19.3°C (66.7°F)) than in other areas. I wonder how a thermal bridge could form there, but I’m not an expert.
3. The humidity level just shocked me: 67%. It’s a "baby room" that is actually only used by a child at night (now no longer because of mold). So I’m wondering where the moisture is coming from. I’m thinking about getting a dehumidifier—what do you think?
Best regards and many thanks
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