ᐅ insufficient sound insulation of interior walls

Hello everyone,

My partner and I moved into our own home about six months ago. We bought the house as a newly built property, ready for first occupancy. It was designed and constructed by the seller.
Over these six months, we have noticed that the house is very noisy. The two rooms directly next to the bathroom/water closet are most affected. The level of privacy you would expect in a bathroom (toilet) is completely missing here. When someone uses the toilet, if you are in one of the neighboring rooms, you feel like you are right there instead of being separate.
Especially at night, when my (pregnant) partner makes one of her many trips to the bathroom, it becomes really exhausting. I could easily describe the consistency and quantity of what she flushes (exaggerated). And when she flushes, it feels like you might get flushed away too.
I understand that 100% soundproofing is impossible, but this seems abnormal to me.
Today, I measured the wall thickness myself (I couldn’t make sense of the structural engineer’s documents). The walls are approximately between 14 and 18 cm (5.5 and 7 inches) thick and, according to the building description, are made of aerated concrete (porous concrete) or calcium silicate bricks.
Can anyone tell me if this is normal? Are there any regulations concerning sound transmission or insulation of interior walls? Could this be a construction defect? If so, how can it be proven?
I hope someone here might be able to help me a bit.
Thank you in advance.

Good evening,

zelos schrieb:

Could this be a construction defect?

No.

The seller specified that the interior walls in the attic or upper floor—depending on whether it is a single- or two-story building—are built from solid materials. It is unlikely to be sand-lime brick (or you would hear even the slightest noise); I would guess aerated concrete instead. Drywall partitions are a good alternative; so you will need to invest in replacing the walls. However, do not replace the walls surrounding the stairwell opening, as they are likely to have a structural function.

Regards, Bauexperte

Have the pipes been soundproofed?
Is it possible that the sound is being transmitted through the ceiling? What is the ceiling construction? Drywall? OSB panels? Is there a gap between the wall and the ceiling? What type of insulation is installed above the ceiling?

Since I have already lived with aerated concrete walls (which are still walls), I tend to think it’s more likely a transmission of noise through something.

What is behind the toilet? Is the knee wall raised by masonry there? -> Resonance chamber?

kaho674 schrieb:
Can't he just put drywall in front of it? As long as there are no door frames in the way, that should be possible, right?

I’ve been wondering about this myself. Does it make sense? Does adding a wall in front of the Ytong wall provide extra sound insulation?
If so, how should it be constructed?

This is something we’re currently dealing with. Since yesterday, my husband has been worried that he’ll be able to hear our daughter’s Skype calls and chatting because the partition wall is only 11.5cm (4.5 inches) thick. The other non-load-bearing walls are 17cm (6.7 inches) thick, so I’m not concerned about those.
During the planning phase, the rooms were assigned differently; only after everything was finished, the rooms were renegotiated like at a bazaar.

In this thread, the original poster was apparently more concerned with the question of construction defects and how to prove them, rather than identifying the cause and fixing the problem.