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Nanopixel11 Dec 2023 01:00Hello everyone,
this concerns the same room (living room) that I mentioned some time ago in this thread, but with a slightly different issue.
Back then, it was about the constantly fogged-up glass on the sliding door. Over time, it became clear that the moisture is not only settling there but also on the ceiling above. This leads to mold repeatedly forming along the entire edge of the ceiling—no matter how often the mold is removed.
Recently, when temperatures dropped below 0°C (32°F) again, the temperature in the middle of the ceiling was about 19°C (66°F), while at the edge it was only 5°C (41°F)! You could directly see how the droplets formed there.
One additional fact that I hadn’t paid attention to before: on this side of the room, there is a balcony above. I only became aware of this when I recently looked at the building plans. (Image attached shows the room on the upper floor with the balcony, and the size of the room underneath with the mold issue is marked with a red dashed line.)
I suspect that the fact that the balcony (18cm (7 inches) concrete slab) is above this edge instead of heated living space significantly contributes to the area being so cold that the ceiling turns into a dripping cave.
How can this situation be improved? Here are my own thoughts; I would appreciate comments on how reasonable these ideas are:
1. Insulate the balcony above + new floor covering. Problems: Limited possible build-up height due to the low threshold of the balcony door. Also, the apartment is currently rented out.
2. Insulate the ceiling on the ground floor, where the balcony is above. Problems: Should insulation be installed on the “warm” side? Insulate the entire ceiling even though only about 1 meter (3 feet) at the edge is necessary? Or just insulate a 1-meter-wide strip and build an encasement around it, with integrated lighting to make it look intentional ;-)
3. Combination of options 1 and 2?
Thanks in advance to everyone who comments.
this concerns the same room (living room) that I mentioned some time ago in this thread, but with a slightly different issue.
Back then, it was about the constantly fogged-up glass on the sliding door. Over time, it became clear that the moisture is not only settling there but also on the ceiling above. This leads to mold repeatedly forming along the entire edge of the ceiling—no matter how often the mold is removed.
Recently, when temperatures dropped below 0°C (32°F) again, the temperature in the middle of the ceiling was about 19°C (66°F), while at the edge it was only 5°C (41°F)! You could directly see how the droplets formed there.
One additional fact that I hadn’t paid attention to before: on this side of the room, there is a balcony above. I only became aware of this when I recently looked at the building plans. (Image attached shows the room on the upper floor with the balcony, and the size of the room underneath with the mold issue is marked with a red dashed line.)
I suspect that the fact that the balcony (18cm (7 inches) concrete slab) is above this edge instead of heated living space significantly contributes to the area being so cold that the ceiling turns into a dripping cave.
How can this situation be improved? Here are my own thoughts; I would appreciate comments on how reasonable these ideas are:
1. Insulate the balcony above + new floor covering. Problems: Limited possible build-up height due to the low threshold of the balcony door. Also, the apartment is currently rented out.
2. Insulate the ceiling on the ground floor, where the balcony is above. Problems: Should insulation be installed on the “warm” side? Insulate the entire ceiling even though only about 1 meter (3 feet) at the edge is necessary? Or just insulate a 1-meter-wide strip and build an encasement around it, with integrated lighting to make it look intentional ;-)
3. Combination of options 1 and 2?
Thanks in advance to everyone who comments.
1A thermal bridge with additional cooling fin function.
Cantilevered concrete slab, also exposed on top.
There are different options – listed in descending order of effectiveness:
The goal is always to either fully block the path of heat flow (complete insulation) or to make the path as long as possible.
1. Remove/cut off the balcony and insulate the remaining concrete slab at the front edge and on top.
2. Insulate the balcony on all sides. For the top surface, 2cm (1 inch) XPS insulation with reinforcement and tiles is sufficient if necessary, resulting in a total build-up height of 4cm (1.5 inches). Insulating the front is difficult due to its shape.
3. Insulate the balcony on the top and bottom while leaving the front edge exposed. The side insulation already reduces the thermal effect significantly. The bottom outside area has almost no effect.
4. Insulate only from the inside. The width of insulation should cover the overhang width plus 1.5m (5 feet), as more does not significantly improve the effect. However, insulating concrete from the inside is problematic because any moisture that gets behind it cannot easily escape. Therefore, this is the least effective and most critical solution from a building physics perspective.
If the balcony is to remain, I would recommend at least option 3, preferably option 2.
Cantilevered concrete slab, also exposed on top.
There are different options – listed in descending order of effectiveness:
The goal is always to either fully block the path of heat flow (complete insulation) or to make the path as long as possible.
1. Remove/cut off the balcony and insulate the remaining concrete slab at the front edge and on top.
2. Insulate the balcony on all sides. For the top surface, 2cm (1 inch) XPS insulation with reinforcement and tiles is sufficient if necessary, resulting in a total build-up height of 4cm (1.5 inches). Insulating the front is difficult due to its shape.
3. Insulate the balcony on the top and bottom while leaving the front edge exposed. The side insulation already reduces the thermal effect significantly. The bottom outside area has almost no effect.
4. Insulate only from the inside. The width of insulation should cover the overhang width plus 1.5m (5 feet), as more does not significantly improve the effect. However, insulating concrete from the inside is problematic because any moisture that gets behind it cannot easily escape. Therefore, this is the least effective and most critical solution from a building physics perspective.
If the balcony is to remain, I would recommend at least option 3, preferably option 2.
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Nanopixel11 Dec 2023 13:55Thanks for the post.
Removing the balcony is out of the question since, as mentioned, the apartment is rented and I can’t simply take the balcony away or want to.
Oh, I should have mentioned: fortunately, the shape of the balcony is not as shown in the building plan; it is just a normal rectangular shape.
I hadn’t considered full insulation all around the balcony like that.
Is the effect really that significant if you insulate underneath and also the front? Can this be quantified? Are aluminum-faced PIR/PUR boards suitable for this, which I still have leftover from insulating the basement ceiling?
Adding 4cm (1.5 inches) on top will be difficult because the balcony door has a very low threshold; I think it would be hard to get even 2cm (0.8 inches) in total.
Removing the balcony is out of the question since, as mentioned, the apartment is rented and I can’t simply take the balcony away or want to.
Oh, I should have mentioned: fortunately, the shape of the balcony is not as shown in the building plan; it is just a normal rectangular shape.
I hadn’t considered full insulation all around the balcony like that.
Is the effect really that significant if you insulate underneath and also the front? Can this be quantified? Are aluminum-faced PIR/PUR boards suitable for this, which I still have leftover from insulating the basement ceiling?
Adding 4cm (1.5 inches) on top will be difficult because the balcony door has a very low threshold; I think it would be hard to get even 2cm (0.8 inches) in total.
Nanopixel schrieb:
This concerns the same room (living room) that I previously mentioned here in this thread, but with a slightly different issue. Why have a balcony at all? - from the linked location, it looks like a ground floor level (???).
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
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Nanopixel11 Dec 2023 18:14I may have described this unclearly.
The photo in the linked thread shows the room with the mold problem on the cold ceiling. This room is located on the ground floor.
The room on the floor above is smaller, probably to create a larger balcony (see building plan). This balcony extends significantly over the mentioned ground floor room and is the cause of the cold, damp ceiling below.
The photo in the linked thread shows the room with the mold problem on the cold ceiling. This room is located on the ground floor.
The room on the floor above is smaller, probably to create a larger balcony (see building plan). This balcony extends significantly over the mentioned ground floor room and is the cause of the cold, damp ceiling below.
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