Good sound insulation requires more than just a material
For good sound insulation, the degree of improvement is primarily dependent on low stiffness of the insulating layer. In comparison with thick insulating layers, thinner layers offer greater stiffness. This was one reason for our development (jointly with specialist professionals) of the liquid cement-based liquid ElascoLoft® sound insulation product which contains coated spherical, sound deadening material.
ElascoLoft has a volume weight of 150 kg per cubic metre. With a mean thickness of 35 mm, we normally achieve an impact sound level improvement from 22 to 24 db. The better sprung the floating screed, the greater the success rate in terms of airborne sound level. In cases of low height,it is better to invest in the thickness of the decoupling sound insulation than in a thick screed.
Ceiling cavities should be filled with a soft sound attenuation compound, wherever possible with a flow resistance of between 5 and 50 kN· s/m4 and to a level of 80 %. Here any fibrous insulation material in accordance with DIN 18165 Part 1 of Type Ww or Wz may be considered.