The present invention relates to a sound rated floor system for inhibiting sound transmission between floors. The system includes a corrugated steel deck; a first layer of cementitious material or board or sheet applied over the corrugated steel deck; a sound insulation mat or board applied over the first layer; a second layer of cementitious material applied over the sound insulation mat or board. The floor system has an IIC rating of at least 25 and the corrugated steel deck provides at least 50 percent of the ultimate load carrying capacity under static and impact loading of the floor system with a floor deflection of at most 1/360 of the floor span.