For the prediction of impact noise, most analytical studies focus on the vibration characteristics of the structure has been concentrated. But, Most of it can not explain the thing that different floors with the same section make a different impact noise. In addition, Resonant amplification of impact noise, caused by indoor air gap, can not be predict by those methods. These limitations is occurred by analytical tools, such as impedance method, does not consider the existence of air gap. This study estimates is performed to assess the validity of fully coupling analysis for predicting impact noise with air gap.