Flanking noise at stacked townhouse entrance stairs

In stacked, wood-framed townhouses, entry stairs for upper units pass through the footprint of lower units. The demising construction between the units, therefore, includes the stairs and floor-ceiling below, as well as the stairwell sidewalls. This irregular construction creates the possibility of significant sound flanking paths between upper and lower units, potentially leading to poor noise isolation performance and occupant dissatisfaction. This paper present practical solutions that have been used to address sound flanking in these areas, including the results of comparative field measurements to evaluate effectiveness. It is concluded that improvements are possible, although wood-framed entry stairs as typically designed are likely to remain an acoustical weakness.