ᐅ How can I prevent mold in the attic?

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.

Is it a cold roof? In the end, the answer to many mold issues is: air! Whether it’s a 2m² (22 sq ft) shower or a 40m² (430 sq ft) pitched roof. You can’t cheat physics. And if it’s a problem in new construction: cross-ventilation is enough to get it under control. Maybe better consult the roofer rather than the carpenter.

HausiKlausi schrieb:

Is it a cold roof? In the end, the answer to many mold problems is air! Whether it’s a 2m² (22 sq ft) shower or a 40m² (430 sq ft) attic roof. You can’t trick physics. And if it’s painful in a new build: cross ventilation is enough to bring the problem under control. Maybe better to ask the roofer rather than the carpenter.

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 just over 40% using a construction dehumidifier. The painter applied a chlorine-based spray, which is intended to be sprayed on the drywall panels to 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 should not become that damp again. Maybe it was just a one-time event after plastering and screeding. We just have to wait and see. Such a dehumidifier easily consumes around 100 kWh per day.

Who installed the drywall panels?
Was the roof designed this way from the start?

T_im_Norden schrieb:

Who installed the drywall panels?
Was the roof planned this way from the start?

An architect designed the house. However, he originally planned skylights in the attic area. We didn’t want those because photovoltaic modules were to be installed on that part of the roof. There was never any talk of windows in the gable. On one side there are bricks; on the other side, facade panels, so it wouldn’t be possible to cut holes later anyway.

The carpenter/roofer installed the drywall covering.

Was the drywall cladding planned that way from the start?

Normally, cold roofs are not covered. If they are, higher standards must be met to prevent mold and avoid moisture buildup.