Hello,
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We bought an older house built in 1971 about 7 years ago. At that time, the bedroom ceiling was repainted and the walls were wallpapered.
Over the years, we have noticed some fogging – meaning the walls have become slightly darker. The painter plans to repaint them again this summer.
Our flat roof was renovated 12 months ago.
Inside, there were never any signs of damp spots, but on the outside, just below the gutter, we could see concrete drips through the plaster, which is why we decided to renovate it.
Now, by chance due to a new lamp, I have noticed light spots on the bedroom ceiling. When I tap on them, they sound hollow. In the bedroom, I find about 7 of these spots spread over 15 sqm (160 sq ft) – each no larger than the width of a hand and scattered. In the other rooms upstairs, we do not have this fogging issue; the ceilings there still look freshly painted. However, even there, when tapping, I can occasionally find a few small hollow spots by chance.
There are no cracks or dark discolorations anywhere on the upper floor.
Could it theoretically be that the roof was more leaky than we thought, causing the reinforcement in the concrete to rust and therefore the plaster to sound hollow in small areas? Or is it more likely just a harmless cause such as old plaster, poor adhesion, or something similar?
I hope it is the latter, because otherwise, we would expect not only small hollow spots but rather longer, larger areas and also cracks in the plaster in these spots, right?
Pictures are really difficult to capture; even in person, you only notice the spots when looking closely.
If this is the wrong section, please move it!
We bought an older house built in 1971 about 7 years ago. At that time, the bedroom ceiling was repainted and the walls were wallpapered.
Over the years, we have noticed some fogging – meaning the walls have become slightly darker. The painter plans to repaint them again this summer.
Our flat roof was renovated 12 months ago.
Inside, there were never any signs of damp spots, but on the outside, just below the gutter, we could see concrete drips through the plaster, which is why we decided to renovate it.
Now, by chance due to a new lamp, I have noticed light spots on the bedroom ceiling. When I tap on them, they sound hollow. In the bedroom, I find about 7 of these spots spread over 15 sqm (160 sq ft) – each no larger than the width of a hand and scattered. In the other rooms upstairs, we do not have this fogging issue; the ceilings there still look freshly painted. However, even there, when tapping, I can occasionally find a few small hollow spots by chance.
There are no cracks or dark discolorations anywhere on the upper floor.
Could it theoretically be that the roof was more leaky than we thought, causing the reinforcement in the concrete to rust and therefore the plaster to sound hollow in small areas? Or is it more likely just a harmless cause such as old plaster, poor adhesion, or something similar?
I hope it is the latter, because otherwise, we would expect not only small hollow spots but rather longer, larger areas and also cracks in the plaster in these spots, right?
Pictures are really difficult to capture; even in person, you only notice the spots when looking closely.
Tolentino schrieb:
Those are probably not perfectly sanded putty spots.
Warning: I’m not an expert and not on site. But based on your description, including the tapping sound, I would guess that.
You can ask the painter when they come to do the painting... But why has the ceiling plaster overall darkened over the years, while only these spots have stayed lighter or become lighter?
So, do you think there’s nothing urgent or serious behind this, like rusting reinforcement, and I can just have it painted over at some point, correct?
guckuck2 schrieb:
Where do you get the idea that the reinforcement would rust there? Who planted that thought in your head?A neighbor. Because the flat roof was leaking. He suggested that water might have penetrated the concrete over a long period, and that could be related. Although I think if the roof had really been that leaky, we would have had visible water stains on the ceiling somewhere on the upper floor, but we didn’t. Otherwise, the reinforcement would rust with every normal water damage, right?
guckuck2 schrieb:
No, due to lack of contact with air.Ok. Could it theoretically be that there are cracks in the concrete from above, meaning from the roof, allowing air to reach the reinforcement? - Which are also scattered across the entire upper floor. Sorry for the silly questions, but the neighbor has made me a bit nervous about this.
But in that case, I would probably have more issues than just a few hollow-sounding spots in the plaster, right?
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