What is the industry standard IIC rating?
Impact Noise. Section 9.11 has no requirements for control of impact noise transmission. Footstep and other impacts can cause severe annoyance in multi-family residences. Builders concerned about quality and reducing occupant complaint will ensure that floors are designed to minimize impact transmission. A recommended criterion is that bare floors (tested with out carpet) should achieve an impact insulation class (IIC) of 55. Some lightweight floors that satisfy this requirement may still cause complaints about low frequency impact noise transmission. Adding carpet to a floor will always increase the IIC rating but will not necessarily reduce low frequency noise transmission. Good footstep noise rejection requires fairly heavy floor slabs or floating floors. Impact noise requirements are being considered for inclusion in future versions of the Code. Source: British Columbia Building Code (Canada) section: Appendix A-9.11.1.1. pg 529 We recommend using an underlayment with an FIIC ratin
