The majority of the acoustic performance through a TLFR Board® lined concrete soffit will come from the density and thickness of the concrete soffit. The TLFR Board® will provide a limited increase in the acoustic performance. The densities of both the stone wool insulation (85kg/m^3) and calcium silicate facing board (1300kg/m^3) can be evaluated by an acoustician to make a judgement on the estimated sound insulation.