Step sound board PAROC SSB 2tj is non-combustible stone wool insulation for use as a sound absorbing layer (spring) for the reduction of impact sound in floating floors. PAROC SSB 2tj can be used both in concrete and timber structures. The fibre orientation in the step sound insulation board is mainly horizontal compared to, for example, a roof slab or ground slab. The horizontal fibre direction gives a lower dynamic stiffness, which means better impact sound insulation. The compressive stress of the product is 40 kPa, which means that the slab can carry a 4000 kg/m2 load during installation and use. The strength of the insulation joints are guaranteed by the tongues and grooves on the long side of the board. The board is faced with natural coloured glass fibre tissue.