87.5 mm lining on a single IntraProfil ® CW75 steel structure with a single layer of 12.5 mm gypsum standard plasterboard GKB(A)/GKBI(H2) on one side, freestanding in front of base wall. No limit with regards to depth of wall cavity. Sound insulation improvement measure with min. 50 mm glass wool up to 12 dB possible.