Protective shell as noise protection against neighbors

Hello,

I moved into my new apartment a little over a week ago, renovated everything myself, and unfortunately had to find out that my walls are very thin and my neighbors are very loud. I am quite desperate because after all these years I had really longed for peace and quiet.
Now I have been searching for a solution online for days and thought I’d also ask here what would be the best option.

So far, my research has shown that I probably need to build a drywall partition; everything else would reduce too little noise to achieve a really good result.

I have 15 cm of depth available for the construction thickness, and the wall area is about 9 sqm.

I am not sure which insulation, which gypsum boards, and what distance to the wall would be best.

At the moment, I am thinking of using Knauf Pianoplatten, Sonorock acoustic rock wool from Rockwool, and placing the whole thing 2 cm away from the original wall.

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

What do I need to consider? And how many dB noise reduction can I expect?

I read online that wood fiber or hemp fiber unfortunately only reduce a maximum of about 10-15 dB, but I think I need much more, therefore 10 cm of rock wool. But I can also find nowhere exact acoustic insulation values for different materials. Maybe I’m just too stupid, but I always look for the -dB rating and find nothing. You only read “the heavier the better.” But what does that mean?

This whole thing will cost me a lot of money and I have big concerns that the result may not be enough and I will continue to be screamed out of bed every morning and hardly have any quiet days.

Thanks for your help, I am grateful for any tips!! :)

Best regards

Oh God, you poor thing... you have my sincere sympathy. Over the course of my life, I've also been through one or the other ordeal.

Is the apartment owned? I assume so if you're considering such investments. If you're renting, honestly, I would immediately pull the emergency brake and choose to escape to another apartment. I've tried almost everything in this regard, from escalation to mental training, but if you want peace, it's hard to unlearn that.

What are you aiming for with the measure (Steinwolle etc)? Such acoustic foam can alter or soften the sound, but not really reduce it. If you hope that after the measure you won't hear anything at all, I think that will be difficult. Only mass helps, meaning: material that is heavy. Stone, for example. But even with that, you will probably only be able to strongly soften the sound image, not reduce it. The only thing I have come across so far that can almost switch off sounds is "active noise cancelling" via headphones. That works great on a plane with turbine noise, for example. But with screaming children on the plane, the technology also reaches its limits.

I am now quite optimistic. Unfortunately, I’m stuck in the rental agreement for 2 years, but apart from the noise, the apartment is exactly what I want. Yesterday, I discovered a panel, Wolf Phonestar Tri 15mm, made of sand, which is supposed to reduce up to 37db, plus the rock wool with about 40-50 db, and another gypsum board with 3db, and I think the combination will do the trick. I have now measured several times with my phone, the noise hardly exceeds 45 db, occasionally with loud stomping it goes up to 75db, which should still be covered. Measured directly on the wall.

Please feel free to give more tips for soundproofing :)

If the sound is transmitted through the construction, your facing shell, despite all specifications, is not a perfect solution. There simply isn’t one.

You need to identify where the sound is coming from. It may be transmitted through the floor or ceiling. And your [vorsatzschale] must be perfectly acoustically separated from it. And your landlord must of course agree to these construction measures or they must be reversible upon moving out.

If the sound is transmitted through the construction, your facing shell, despite all specifications, is not a perfect solution. Simply put, there isn't one.

Yes, I have already learned that the construction must be installed floating. I also have great concerns that this will not be the solution. But I don't know what else to do.

I think the majority comes through the wall, since that is the weakest point of the construction, stomped on over the floor. Since I don't hear the neighbors above and below me, I assume that the ceiling and floor are significantly better than the one side wall.