Flanking Probs
Specifier/Regulator
- Feb 1, 2020
- 3
Hi there
I am really struggling to find decent advice. I am willing to pay for advice but cannot seem to find the correct professional who really understands the issue.
I have a 3 story apartment building which was built in the 1990's. It has solid concrete floors with a 20cm slab between each flat. The slab sits in 150mm pumice thermal blocks. In many other countries, the concrete slab would rest on the outside blocks. In the UK it is common to stop the intermediate floor to rest on the inside blocks so that the 50mm cavity is maintained from top to bottom of the building. See photo enclosed
The windows on each floor are above each other and when the flats were built, the cavities were not closed as they would be today. In addition, if the flats were built today there would be an acoustic flanking "sausage" of rockwool (covered in plastic) at each floor layer.
It has plastic windows which sit in the cavity. They are attached with a few "groundings" but I believe as there is only a section of PVC between the window and the cavity, sound is travelling up and down the 50mm cavity.
I have two ideas. One is to fill the cavity with the thermal insulation "beads". I know these are not designed for acoustic insulation but my idea is the clear air gap would be filled. Surely these beads would acts in a similar way to acoustic Rockwool which is not that dense?
A second idea is to remove the skirting boards and drill the wall at 100mm centers. Then to inject a small amount of filler foam to re create a solid flanking strip. I have a Borescope with a rotating camera so I could confirm that the foam strip was continuous with no air gaps.
Does anybody have any suggestions where I can look for advice or acoustic properties for thermal insulation beads? I don't want to blow in Rockwool due to lots of reported issues with wicking and retaining water. The beads are waterproof.
Any advice welcome?
I am really struggling to find decent advice. I am willing to pay for advice but cannot seem to find the correct professional who really understands the issue.
I have a 3 story apartment building which was built in the 1990's. It has solid concrete floors with a 20cm slab between each flat. The slab sits in 150mm pumice thermal blocks. In many other countries, the concrete slab would rest on the outside blocks. In the UK it is common to stop the intermediate floor to rest on the inside blocks so that the 50mm cavity is maintained from top to bottom of the building. See photo enclosed
The windows on each floor are above each other and when the flats were built, the cavities were not closed as they would be today. In addition, if the flats were built today there would be an acoustic flanking "sausage" of rockwool (covered in plastic) at each floor layer.
It has plastic windows which sit in the cavity. They are attached with a few "groundings" but I believe as there is only a section of PVC between the window and the cavity, sound is travelling up and down the 50mm cavity.
I have two ideas. One is to fill the cavity with the thermal insulation "beads". I know these are not designed for acoustic insulation but my idea is the clear air gap would be filled. Surely these beads would acts in a similar way to acoustic Rockwool which is not that dense?
A second idea is to remove the skirting boards and drill the wall at 100mm centers. Then to inject a small amount of filler foam to re create a solid flanking strip. I have a Borescope with a rotating camera so I could confirm that the foam strip was continuous with no air gaps.
Does anybody have any suggestions where I can look for advice or acoustic properties for thermal insulation beads? I don't want to blow in Rockwool due to lots of reported issues with wicking and retaining water. The beads are waterproof.
Any advice welcome?
