Technical Booklet G Resistance to the Passage of Sound·Page 53·2.108
Plaster or plasterboard finish for masonry inner leaf without separating floor
Where there is no separating floor with wall type 3.1 or 3.3 and the masonry inner leaf has at least 120 kg/m² mass, it may be finished with plaster or plasterboard of minimum 10 kg/m² mass per unit area.
Where there is no separating floor with separating wall type 3.1 or 3.3, and the masonry inner leaf of the external wall has a mass of at least 120 kg/m2 excluding finish, then the inner leaf of the external wall may be finished with plaster or plasterboard of minimum mass per unit area 10 kg/m2.
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