Soundproofing in gallery airspace on the upper floor

We are planning a house with a gallery or open space approximately 300cm x 360cm in the living-dining room. The exterior walls will be Poroton bricks 42.5cm. The interior walls mostly 11.5cm hollow bricks. The bedrooms and bathroom are on the upper floor. Now we are concerned that the noise level will be very noticeable upstairs due to the thin interior walls (music, TV, etc.). Yes, we already knew beforehand that with an open space/gallery on the upper floor, increased noise levels would have to be expected. We have now asked the construction company whether 17.5cm walls could be used instead of 11.5cm to reduce sound transmission through the walls. The company said it would not make much difference. Only if we used sand-lime bricks on the corresponding walls on the upper floor would it help. Specifically, it concerns 2 walls each 450cm long (bedroom and children's room) that border directly on the gallery/open space. The construction company wants a surcharge of €1100 for this (instead of 11.5cm hollow bricks now 11.5cm sand-lime bricks). Does anyone have experience with open spaces and noise? Is the surcharge justified? Construction planning attached as an annex.

I don't believe that KS will really bring much here, as long as you don't pay special attention to soundproofing at the doors. That is likely the bigger weak point. But I also wouldn't create an air space ...

We had exactly the same idea and after many discussions with the friendly architect, we moved away from it and shifted the gallery from the living/dining area to the large hallway area. A corresponding soundproof door will be installed between the living/dining area. Additionally, we are building with KS on the ground floor. The weak points are definitely the doors... not the walls.

Regards, Steffen

Hello!

Poroton also offers interior wall bricks with increased bulk density. According to the data sheets, these are significantly more sound-absorbing. The additional cost should be marginal; in the Wienerberger price list, they are listed at the same price.

I consider mixing Poroton and KS within one floor a very bad idea. Brick and KS have different shrinkage, drying, and thermal expansion behaviors. You should consult an expert beforehand to avoid ending up with a building full of small cracks.

So far, I have always read that the material of the exterior wall should be the same as the material of the interior wall.

Best regards,

Andreas

Just opened the plan. I think with that layout, you can forget any consideration about KS, unless you also install soundproof doors right away. You will hear everything upstairs.

If you want quiet there, get rid of the open space. Or if you keep the open space, then a glass partition between the open space and the upstairs hallway. But to me, that has a bit of a cage-like feeling.

We considered something like that briefly, especially my wife thinks it's really stylish. But the disadvantages deterred them from it.

Open spaces, galleries, etc. are a great and stylish thing, but in my opinion they only work for house sizes of 300 sqm and up.

Best regards,

Andreas

Oh dear. Then it doesn't work for us at all. We only have about 230 sqm.

Seriously: It of course depends on the floor plan. We have the open space with a 20 sqm hallway. It works very well there.

Regards, Steffen