ᐅ Poor external sound insulation with thermal insulation bricks

Our new house (built in 2011) was constructed using insulated bricks. Both the interior and exterior walls were finished with a breathable plaster. We now enjoy a very good indoor climate and effective thermal insulation, but unfortunately, we have been shocked to find that our exterior walls provide very little soundproofing against outside noise. In particular, the gable walls, which are perpendicular to the street, seem to capture the outdoor noise and amplify it almost like a resonance chamber. If you press your ear against one of these exterior walls as a car passes by, it feels as if the car is driving inside the wall. We have contacted the brick manufacturer about this issue. They are not aware of any sound insulation problems related to this product.

Has anyone else had similar experiences with insulated bricks? What measures have you taken to improve soundproofing afterward? We would be very grateful for any advice.

Hello,

bauX2011 schrieb:
Our new house (built in 2011) was constructed using thermal insulation bricks. It was plastered inside and outside with breathable render...., but unfortunately, we have to realize that our exterior walls hardly reduce outside noise.

Is there no sound insulation certification? Additionally, it should be clarified whether the noise is structure-borne sound (transmitted through the floor/foundations) or airborne sound.

Best regards

No, there is no soundproofing certification. Should there even be one? Who would arrange it? Who carries it out? What does it cost and what benefits does it provide? How can you determine whether the noise is structure-borne sound or airborne sound? Our experts (architect, construction company, structural engineer, brick manufacturer) simply leave us to deal with the problem on our own. In purely theoretical terms, the brick should provide adequate sound insulation due to its weight, and what we hear actually shouldn’t be audible. But the reality is that you can have a conversation through an exterior wall.

Hello,

bauX2011 schrieb:
No, there is no sound insulation certificate. Should there be one? Who arranges it? Who carries it out? What does it cost and what is the benefit? How can you determine whether it is structure-borne sound or airborne sound? Our experts (architect, construction company, structural engineer, brick manufacturer) just leave us alone with the problem. Mathematically, the brick should provide sufficient sound insulation due to its weight, or what we hear should actually not be audible. But it’s just like that—you can have a conversation through an exterior wall.

If by "thermal insulation bricks" you mean perlite- or mineral-filled hollow bricks and these were actually used, the cause could be missing or improperly installed perimeter strips. These are installed before laying the screed to prevent sound bridges. I once had a customer in Düsseldorf who simply cut off these perimeter strips during site cleanup.

A sound insulation report is prepared by the structural engineer and costs around 3,000 to 4,000 euros. It is required when a specific sound insulation value is mandatory.

From how it reads, you will probably need to hire an external building expert to identify the cause of the noise disturbance. In a completed house, there can be many possible causes; missing perimeter strips are just one example. Based on the findings from the inspection, you can then push your supplier, unless you have also cut off the perimeter strips yourself.

Kind regards

Thermal insulation bricks always provide significantly poorer sound insulation compared to traditional bricks. This is due to the nature of the material, as these bricks have much less mass.

For a brick with a thickness of 36.5 cm (14 inches) and an excellent thermal insulation U-value of about 0.20 (T or W 07 or 08), you can expect a sound insulation level of approximately 43 dB (at best 45 dB). This is quite low and actually allows people to have a conversation through the wall.

Such a brick is primarily composed of air...

Nevertheless, there may be defects that further worsen the situation, and these should be examined by an expert, preferably one who is sworn and publicly authorized.

Hans_Meier schrieb:
...Such a brick mainly consists of air...

That's right! Maximum sound insulation (airborne noise) and maximum thermal insulation are physically incompatible! Therefore, it makes sense to combine the advantages of different components in the overall exterior wall design according to their respective strengths, meaning a monolithic structure is rarely the most effective solution overall!

Best regards