ᐅ Hatch Cover for Attic Stairs – User Experiences

Hello everyone,

I wanted to ask for your ideas or experiences with the following unusual issue.

In our newly built single-family home, we installed a Dolle attic ladder to an unheated pitched attic space. During the heating season, I noticed moisture collecting on the sides of the hatch cover. I thought, aha – cold and warm air are meeting – a leak. I reported this directly to the carpenter, who checked the seals on the frame; everything was fine. However, on the hatch cover itself, he noticed it was warped. It was bowed upward in the middle and downward toward the corners – like a banana. Not extremely obvious visually, but you can see it if you look from the right angle and follow the edges.

So the hatch cover was replaced with a new one. A few days later, the same phenomenon occurred, with the cover warping the same way. The carpenter was puzzled; they hadn’t encountered this problem before. An inquiry was made to Dolle and it is still unresolved.

Meanwhile, the old cover, which is stored at the carpenter’s workshop, has warped back and is now straight again.

Has anyone else experienced this problem? Do you have any ideas about what might be causing it?

Hello,

I would like to raise the question of humidity levels. Perhaps the values have changed significantly during the heating period?
Are we talking about the screed heating program or regular heating during winter?

Normally, with regular heating to room temperature, the humidity tends to decrease rather than increase...

Stick a hygrometer under the hatch, then place it on the hatch on the attic side and compare the readings. I expect the relative humidity to be significantly lower downstairs.

Simon-189 schrieb:

Hello,

I’d like to raise the question about indoor humidity levels. Could the values have increased or decreased significantly during the heating period? Are we talking about the screed heating program or regular winter heating here?

Because with regular heating to living room temperatures, humidity usually tends to drop rather than rise...

Regular winter heating, the first winter of course, so overall the humidity is still relatively high but has been gradually decreasing over the past months. We have temperature and humidity sensors throughout the house. If we don’t ventilate for one day, the indoor humidity on the upper floor is still around 61-64%. When we moved in last summer, it was over 75%. So there has been some progress, but there’s still quite a way to go.

Schorsch_baut schrieb:

Try placing a hygrometer under the hatch and then move it to the hatch on the attic side to compare the values. I’d guess the relative humidity is much lower downstairs.

Actually, it’s the other way around. The air inside the house is warm and humid, while the attic is cold and dry. But the hatch should generally be able to handle that, otherwise this would be a common issue in many new builds, right?

Then the hatch would have to bulge the other way, with the bump facing downward. The drier side shrinks and has the smaller surface area. Therefore, my assumption is that the relative humidity beneath the hatch is lower than on the hatch.

Ubibubi schrieb:

otherwise this would happen in lots of new buildings, right?

How do you know it doesn’t? Most attics have very dim lighting, so it’s easy to miss. And people don’t go up there very often. As long as it’s just a little moisture, you don’t notice it that easily. Especially not in summer.

Basically, I would say that the ceiling should be able to handle that. Its intended function is exactly to be between the warm, humid indoor air and the cold, dry attic. Here, we’re talking about absolute humidity. The relative humidity in the attic is around 70% or more. No wonder, since it roughly follows the outdoor air (because the attic is not completely airtight), and during damp, cold weather it can easily exceed 90%.