In Nättraby, Karlskrona, Sweden, this innovative project is erected. It is a six-storey building comprising 23 dwellings, finished in April 2023. It is a CLT building with normal to high acoustic performance, following at least the Swedish minimum requirements, in acoustic figures, DnT,w+C50-3150 ≥ 52 dB and L´nT,w+CI,50-2500 ≤ 56 dB. Our mission was to carry out design of a new raised floor system with LVL plates on top, design CLT structure with integrated WC / installation modules, predict sound insulation of structural components and flanking transmission through junctions, and finally to carry out verification measurements. The developer is Svensk Bostadsutveckling and the architect is Wingårdhs Architecture.