Improving sound insulation of old timber floor constructions 1917/1937 in multi-storey housing – Field case study & Perspectives

In Denmark, the first national requirements for sound insulation in housing were published in 1961. Most complaints about neighbour noises are from people in multi-storey housing (MSH) and relate to impact sound from both children and adults, although also annoyance due to airborne sounds are common. A mapping of the housing stock timeline and construction types showed that more than half of the MSH dwellings were built before 1961 and that most housing is brick-built with timber floor constructions.
In a project investigating air particle transfer vertically between dwellings, we had the opportunity to make a case study with test of airborne and impact sound insulation before and after mounting a new independent ceiling below the existing construction.
Measurements were made for eight floor constructions in housing built 1917/1937. The acoustic classification standard DS 490 has six classes A-F with Class C being the building code requirement for new housing. Before renovation, the airborne sound classes were D-E and impact sound F. After mounting of the new ceilings, the R’w values were improved ~6 dB and L’n,w ~12 dB, implying all results were Class C, thus complying with limits for new build. The paper will describe experiences from the case study and the perspectives concerning preparation of acoustic regulations for renovated dwellings and mandatory acoustic labelling.