ᐅ Sound insulation for gallery void/open space on the upper floor

We are planning a house with a gallery or open space approximately 300cm x 360cm (10ft x 12ft) in the living-dining area. The exterior walls will be made of Poroton bricks, 42.5cm (17 inches) thick. The interior walls will mostly be 11.5cm (4.5 inches) hollow bricks.

The bedrooms and bathroom will be on the upper floor. We are concerned that noise will be very noticeable upstairs due to the thin interior walls (music, TV, etc.). Yes, we were already aware that noise levels would be higher with an open gallery/void on the upper floor.

We asked the builder if they could use 17.5cm (7 inches) thick walls instead of 11.5cm to reduce sound transmission through the walls. The company said that wouldn’t help much. They said that only if we use sand-lime bricks on the relevant upper floor walls would it make a difference.

This specifically concerns two walls, each 450cm (15 feet) long (bedroom and children’s room), which directly border the gallery/open space. The builder wants an additional charge of €1100 for this change (switching from 11.5cm hollow bricks to 11.5cm sand-lime bricks).

Does anyone have experience with open spaces and sound transmission? Is the extra cost justified?

The construction plan is attached.

I don’t think that sand-lime brick will make much of a difference here, unless you also pay special attention to sound insulation at the doors. That is probably the bigger weak point.

However, I also wouldn’t recommend creating an air gap ...

We had exactly the same idea, but after many discussions with the friendly architect, we moved away from it and relocated the gallery from the living/dining area to the large hallway. A suitable soundproof door will be installed between the living/dining area. Additionally, we are building the ground floor with sand-lime brick. However, 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 datasheets, these have significantly better sound insulation. The additional cost should be minimal; in the Wienerberger price list, they are listed at the same price.

I consider mixing Poroton and calcium silicate bricks within the same floor to be a very bad idea. Bricks and calcium silicate blocks have different shrinkage, drying, and thermal expansion behaviors. You should consult an expert beforehand to avoid ending up with a house full of small cracks.

So far, I have always read that the material used for exterior walls should be the same as for interior walls.

Best regards,

Andreas

I just opened the plan. With this layout, I don’t think it’s worth considering sand-lime bricks unless you also install soundproof doors right away. You’ll end up hearing everything upstairs.

If you want quiet up there, remove the open space. Or if you keep the open space, then add a glass partition between the open space and the upstairs hallway. In my opinion, though, that has a bit of a cage-like feel.

We briefly considered something like that too, especially my wife thought it looked very stylish. But the downsides convinced her otherwise.

Open spaces, galleries, and so on are great and stylish features, but in my opinion they only really work in houses of 300 sqm (3,230 sq ft) or larger.

Best regards,

Andreas

Oh dear. Then it definitely won’t work for us. We only have about 230 sqm (2,474 sq ft).

Seriously: It obviously depends on the floor plan. We have an open space over a 20 sqm (215 sq ft) hallway. That works very well.

Regards, Steffen