The attic of our new build is accessed by a pull-down ladder. There are no windows there – neither in the gable nor any roof windows.
During the building drying phase (after plastering and after the screed), the hatch to the attic was completely closed. This was explained to us as a way to prevent mold growth. Since then, the pull-down ladder has been installed, and the attic has been lined with drywall panels. Now we notice a musty smell there, and mold spots are forming on the panels.
What can be done at this point? I have also asked the carpenter for advice at the same time.
During the building drying phase (after plastering and after the screed), the hatch to the attic was completely closed. This was explained to us as a way to prevent mold growth. Since then, the pull-down ladder has been installed, and the attic has been lined with drywall panels. Now we notice a musty smell there, and mold spots are forming on the panels.
What can be done at this point? I have also asked the carpenter for advice at the same time.
Schimi179118 May 2021 07:02Heidi1965 schrieb:
An architect designed the house.
...No divided light windows 🙂Heidi1965 schrieb:
...
They must know what they are doing
...Unfortunately, reality often shows the opposite.T
T_im_Norden18 May 2021 08:02Try searching online for "building material knowledge" and "cold roof."
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hampshire18 May 2021 08:10A cold roof is characterized by ventilation in the area of the rafters. This allows moisture to be carried away. Modern houses can only achieve the required energy efficiency if they are properly insulated and sealed. The insulated and sealed area is also called the thermal envelope. In a cold roof, the attic is not part of the thermal envelope. If you have a cold roof and ventilation is not provided, this is a construction defect.
HausiKlausi18 May 2021 23:41The suggestion to use an anti-mold spray instead of ventilation here makes me question the specialist’s qualifications. Let me emphasize again: the spray addresses the symptoms, not the cause! Two sufficiently large opposite holes with ventilation grilles—and the problem is solved.
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Heidi196519 May 2021 06:47It is not possible to drill into facade panels.
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Myrna_Loy19 May 2021 09:12Heidi1965 schrieb:
The roof is insulated and covered with drywall panels, but there is no heating up there. The roofer and carpenter are the same person. We have now reduced the humidity from 85% to about 40% using a construction dryer. The painter applied a chlorine-based spray to treat the drywall panels and kill the mold. The carpenter/roofer says that once we have lowered the humidity and keep the hatch between the upper floor hallway and the attic closed, it shouldn’t get that damp again. Maybe this was just a one-time event after the plastering and screed work. We will have to wait and see. Such a construction dryer easily uses about 100 kWh per day. If the roof is insulated—not just the ceiling of the top floor—then it’s not a cold roof.
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