ᐅ Hollow bricks and soundproofing – looking for experiences

I cannot confirm the poor sound insulation between floors that has been mentioned. Although we have solid brickwork, the construction of the concrete ceiling is as described here: the ceiling is recessed by about 20 cm (8 inches) all around, with insulation and a hollow brick placed in front of it. The sound insulation from outside is acceptable (not outstanding), and the same applies to the interior walls, where different wall thicknesses are noticeable.

tomtom79 schrieb:

Is it possible to use calcium silicate blocks with facing brick without external thermal insulation composite systems (ETICS)?

Absolutely. In the past, a simple air gap was left between the inner and outer walls; nowadays, this enlarged cavity is filled with mineral wool insulation. We chose this method partly because we prefer to avoid ETICS. It is somewhat more expensive than ETICS with render, but you get specialized components for different functions: calcium silicate blocks for load-bearing and sound insulation, mineral wool for thermal insulation, and facing brick as a durable weather barrier (and additional sound insulation due to its mass), which also effectively stores heat.

K1300S schrieb:

However, I cannot confirm the poor sound insulation between floors from our current house. Although we have filled bricks, the concrete ceiling is constructed as described here: the ceiling is recessed by about 20 cm (8 inches) all around, with insulation and a hollow brick placed in front of it. I find the sound insulation from outside acceptable (not outstanding), and the same goes for the interior walls, although different wall thicknesses are noticeable.

If you only get average sound insulation with filled bricks, the issue is likely the windows and not the bricks.

Snowy36 schrieb:

If you only get average sound insulation with filled bricks, then the problem is with the windows, not the bricks.

I tend to doubt that, but thank you for your analysis.

It’s probably just that I previously lived in a house with walls made of sand-lime bricks plus facing bricks. That’s a completely different level. And honestly, from a purely physical point of view, I don’t see why the quite porous filling should make such a huge difference. This also seems to be confirmed by the technical data sheets (here from Wienerberger):

T7-MW: 47.2 dB
T8-P: 46.4 dB
T10-36.5: 45.5 dB

Yes, the unfilled T10 is the worst of the three, but the difference isn’t huge (despite the logarithmic scale).

For comparison: The 15 cm (6 inches) load-bearing shell of our sand-lime brick wall alone already achieves a sound insulation rating of 54.6 dB. Including insulation and facing brick, you can add another 8 dB to that. (As I just noticed, the exterior render of a brick wall is already included above. Those rascals...)

K1300S schrieb:

For comparison: Just the 150mm (6 inches) load-bearing shell of our sand-lime brick wall already achieves a sound insulation rating of 54.6 dB. Including insulation and with facing brick, you can add another 8 dB. (As I just noticed, the exterior render of a brick wall is already included above. Sneaky ...)

The difference is really striking. Still, standard windows are around 32 dB. With window sizes nowadays, the wall almost doesn’t matter anymore.