ᐅ Impact sound insulation – Screed causes hollow noise – New semi-detached house
Created on: 9 Nov 2020 14:07
H
heimerHello,
we moved into our newly built semi-detached house two weeks ago – my brother lives in the other half.
135m² (1455 sq ft) of living space plus a basement – solid construction – Poroton blocks.
First of all – we hear absolutely nothing from the other semi-detached house... it was built with 24cm (9.5 inches) soundproofing bricks RD1.4 and a 4cm (1.5 inches) insulation gap.
What really bothers us, and what we find hard to believe is normal nowadays:
-> Every step echoes loudly throughout the entire house.
It’s even worse barefoot or in socks than with shoes.
This is the same on every floor – no matter if the floor covering is glued vinyl or tiles.
What stands out – rooms like the kitchen and the dressing room are much better. I suspect this is because there is weight on the floor, preventing it from vibrating.
We used to live in a 40-year-old rental house – and it was nowhere near this bad there.
When our little one, who weighs 15kg (33 lbs), runs around in his bedroom on the first floor, the whole place thunders... you almost fall off the couch...
About the floor structure (from the screed installer’s quote/invoice):
6cm (2.4 inches) EPS 100kPa WLG035 thermal insulation (according to DIN4108-10) including edge strips
35-3 Rolljet WLG045 impact sound insulation panel fixed with staples
6cm (2.4 inches) anhydrite liquid screed CAF-C25-F4
On top of that either glued design vinyl or tiles – the thudding noise remains the same.
What could be causing this?
Could the screed be to blame?
The screed in my brother’s house was done by the same company – and they have exactly the same problem... :-(
Thank you in advance
we moved into our newly built semi-detached house two weeks ago – my brother lives in the other half.
135m² (1455 sq ft) of living space plus a basement – solid construction – Poroton blocks.
First of all – we hear absolutely nothing from the other semi-detached house... it was built with 24cm (9.5 inches) soundproofing bricks RD1.4 and a 4cm (1.5 inches) insulation gap.
What really bothers us, and what we find hard to believe is normal nowadays:
-> Every step echoes loudly throughout the entire house.
It’s even worse barefoot or in socks than with shoes.
This is the same on every floor – no matter if the floor covering is glued vinyl or tiles.
What stands out – rooms like the kitchen and the dressing room are much better. I suspect this is because there is weight on the floor, preventing it from vibrating.
We used to live in a 40-year-old rental house – and it was nowhere near this bad there.
When our little one, who weighs 15kg (33 lbs), runs around in his bedroom on the first floor, the whole place thunders... you almost fall off the couch...
About the floor structure (from the screed installer’s quote/invoice):
6cm (2.4 inches) EPS 100kPa WLG035 thermal insulation (according to DIN4108-10) including edge strips
35-3 Rolljet WLG045 impact sound insulation panel fixed with staples
6cm (2.4 inches) anhydrite liquid screed CAF-C25-F4
On top of that either glued design vinyl or tiles – the thudding noise remains the same.
What could be causing this?
Could the screed be to blame?
The screed in my brother’s house was done by the same company – and they have exactly the same problem... :-(
Thank you in advance
Hello questioner.
It is certainly not possible to give a clear answer from a distance.
The insulation system you are using is a combined thermal and impact sound insulation with a specified dynamic stiffness S15 and a thermal conductivity (WLG) of 0.045 W/mK.
With a panel thickness of 35/32 mm (1.4/1.26 inches), you can calculate where the tendency should go:
Either towards a more compressive thermal insulation or a softer impact sound insulation. Having both optimized at the same time is not possible because the requirements for impact sound and thermal insulation conflict and interfere with each other.
Products used as impact sound insulation must have sufficient cushioning capability, which is characterized by the dynamic stiffness s’ of the insulation layer including the air enclosed within it.
For the specific application as impact sound insulation, products made of expanded polystyrene (EPS) and mineral wool (MW) are suitable.
These products are classified into stiffness groups. The following rule applies: the better the dynamic stiffness, the thinner the impact sound insulation can be. The lower the s’, the higher the impact sound improvement.
In your house, it seems that the soundproofing requirements might possibly not be met.
However, it must be taken into account that in owner-occupied single-family houses, soundproofing is not as important as in multi-family buildings.
And since the two halves of the house are also acoustically sufficiently separated, I see difficulties in making a strong case against the general contractor.
However, there should be no drumming or rattling when walking on the floor surface; in other words, the soundproofing requirements must not be reduced to zero.
Maybe I have not contributed enough to the clarification here, but hopefully I could still give a small hint.
Kind regards, KlaRa
It is certainly not possible to give a clear answer from a distance.
The insulation system you are using is a combined thermal and impact sound insulation with a specified dynamic stiffness S15 and a thermal conductivity (WLG) of 0.045 W/mK.
With a panel thickness of 35/32 mm (1.4/1.26 inches), you can calculate where the tendency should go:
Either towards a more compressive thermal insulation or a softer impact sound insulation. Having both optimized at the same time is not possible because the requirements for impact sound and thermal insulation conflict and interfere with each other.
Products used as impact sound insulation must have sufficient cushioning capability, which is characterized by the dynamic stiffness s’ of the insulation layer including the air enclosed within it.
For the specific application as impact sound insulation, products made of expanded polystyrene (EPS) and mineral wool (MW) are suitable.
These products are classified into stiffness groups. The following rule applies: the better the dynamic stiffness, the thinner the impact sound insulation can be. The lower the s’, the higher the impact sound improvement.
In your house, it seems that the soundproofing requirements might possibly not be met.
However, it must be taken into account that in owner-occupied single-family houses, soundproofing is not as important as in multi-family buildings.
And since the two halves of the house are also acoustically sufficiently separated, I see difficulties in making a strong case against the general contractor.
However, there should be no drumming or rattling when walking on the floor surface; in other words, the soundproofing requirements must not be reduced to zero.
Maybe I have not contributed enough to the clarification here, but hopefully I could still give a small hint.
Kind regards, KlaRa
Hello KlaRa,
I should add that we built the house together with an architect and did most of the work ourselves.
I have now also taken a sound level measurement in the floor below. Whenever an adult walks barefoot or in socks, the noise level is always over 70 dB at maximum… no matter which floor.
It’s all very strange.
As I mentioned, if you stomp firmly right next to the glass cabinet, the glasses inside rattle.
I should add that we built the house together with an architect and did most of the work ourselves.
I have now also taken a sound level measurement in the floor below. Whenever an adult walks barefoot or in socks, the noise level is always over 70 dB at maximum… no matter which floor.
It’s all very strange.
As I mentioned, if you stomp firmly right next to the glass cabinet, the glasses inside rattle.
heimer schrieb:
As mentioned, if you step firmly next to the glass cabinet, the glasses inside the cabinet rattle. However, this should not happen with a CAF system having a nominal thickness of 60mm (2.4 inches).
Four years ago, I dealt with a similar case involving a raised floor system in a courthouse.
In the end, the entire apartment (high-end finish, 4th floor in a prestigious building) had to be vacated, and the screed completely removed.
Are there records of the screed installation, delivery notes, or similar documents that might allow for a cautious deduction of an under-installed thickness?
Rattling and clinking glasses can be related to an undersized, and therefore easily vibrating, load distribution layer, less so to the impact sound insulation.
Best regards, KlaRa
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