Abstract
Inside of the Housing Performance Indication System, indications related with sound environment are highly demand by residents. These affect to claim and trouble, and become civil suit factor. Therefore, to promote spreading indication of house performance are much required. In this study, focusing to the heavy floor impact sound control grade, we simplify the evaluation method criteria and proposing slab thickness grade conversion. Slab thickness grade conversion is new method of calculation with the indicated slab thickness and consideration change of sound receiving room area.