ᐅ Additional wall layer as soundproofing against neighbors

Hello,

I moved into my new apartment about a week ago, renovated everything myself, and unfortunately found out that my walls are very thin and my neighbors are very loud. I’m quite desperate because after all these years I was really looking forward to some peace and quiet.

I’ve been searching online for days for a solution and thought I’d ask here what would be the best approach.

So far, my research suggests that I should build a secondary wall (a stud wall with insulation), as everything else would reduce noise too little to achieve a really good result.

I have about 15 cm (6 inches) of space available for the wall construction depth, and the wall surface is approximately 9 square meters (97 square feet).

I’m not sure which insulation material, which plasterboards, and what distance from the original wall would be best.

At the moment, I’m considering acoustic plasterboards from Knauf, acoustic mineral wool Sonorock from Rockwool, and placing it about 2 cm (1 inch) away from the original wall.

Am I on the right track? Does anyone have experience with internal soundproofing in apartments?

What should I watch out for? And how much noise reduction in dB can I realistically expect?

I’ve read online that wood fiber or hemp fiber insulation only reduce noise by about 10–15 dB maximum, but I think I need much more, so I’m planning on 10 cm (4 inches) of mineral wool. However, I haven’t found any detailed acoustic insulation values for different materials anywhere. Maybe I’m missing something, but whenever I search for “-dB” ratings, I find nothing. People always say “the heavier, the better,” but what exactly does that mean?

This is going to cost me a lot of money, and I’m really worried that the result might not be sufficient and I’ll keep being woken up every morning and hardly have any quiet days.

Thanks for your help—I’m grateful for any advice!! 🙂

Best regards

Oh god, you poor thing... you have my sincere sympathy. Over the course of my life, I’ve also been through some tough experiences.

Is the apartment owner-occupied? I assume so if you are considering such investments. If you are renting, to be honest, I would immediately cut my losses and move to another apartment. I’ve tried almost everything in that regard, from confrontation to mental training, but if you want peace and quiet, it’s hard to unlearn that habit.

What do you hope to achieve with the measure (rockwool insulation, etc.)? Acoustic foam can alter or reduce noise somewhat, but it won’t really eliminate it. If you expect that after the treatment you won’t hear anything at all, I think that will be difficult. Only mass helps here—that means material that is heavy. Stone, for example. But even with that, you’ll likely only be able to significantly reduce the sound rather than eliminate it. The only thing I’ve encountered so far that can almost completely block out noise is active noise canceling through headphones. That works great, for example, on airplanes with engine noise. But even that technology reaches its limits with screaming children on a plane.

I’m feeling quite optimistic now. Unfortunately, I’m stuck with a rental contract for another two years, but apart from the noise, the apartment is exactly what I want.

Yesterday, I discovered a panel called Wolf Phonestar Tri 15mm (0.6 inches), made from sand, which is said to reduce noise by up to 37 dB. Along with mineral wool insulation that provides about 40-50 dB, and an additional gypsum board with 3 dB, I think the combination will be effective. I’ve measured the noise levels several times using my phone; the noise rarely exceeds 45 dB, but occasionally with loud footsteps it goes up to 75 dB, which should still be within acceptable limits. These measurements were taken directly at the wall.

I’d appreciate any further tips on soundproofing 🙂

When sound is transmitted through the structure, your facing wall, despite all specifications, is not a perfect solution. Simply put, such a solution does not exist.

You need to identify where the sound is coming from. It might be transmitted through the floor or ceiling. Your stud wall must be acoustically isolated from this perfectly. And, of course, your landlord must agree to these construction measures or they must be reversible when you move out.

guckuck2 schrieb:

If sound is transmitted through the structure, your secondary wall, despite all specifications, is not a perfect solution. Simply put, there is no perfect solution.

Yes, I have also learned that the structure needs to be installed as floating. I am very concerned that this might not solve the problem. However, I don’t know what else to do.

I think most of the sound is coming through the wall, since that is the weakest point of the structure, with footstep noise on the floor. Since I don’t hear the neighbors above or below me, I assume that the ceiling and floor are much better insulated than the one side wall.