Traditionally, better sound insulation has been a matter of increasing the weight/mass of a structure. With the SL-deck, however, it is possible to achieve a very sound insulating structure with very thin slab elements.
In Denmark, 18cm SL-decks are used in most residential projects to fulfill sound requirements while alternative systems require thicker and heavier pieces to fulfill the same requirements.
Effects of internal arches
An arch is stiffer than a straight structure and produces higher eigenfrequencies, which is beneficial, as the most difficult frequencies to dampen are in the low end of the spectrum. In the SL-deck, the self-compacting concrete is casted as a series of arches on top of the light blocks, which helps the SL-deck achieve very high sound insulation properties.
Combination of materials
Normal heavy concrete and light-weight concrete have different eigenfrequencies, which vibrate differently together. As a result, sound transmission is significantly reduced when traveling from one material to the other giving the SL-deck very high sound insulation properties despite of its low weight and density.
The SL-deck sound insulation properties has been tested by DELTA according to EN ISO 717-2:2013 with the following results: