The Impact Sound Insulation of Pre-Loaded Timber Floating Floors on a Concrete Slab

When impact sound tests are carried out in new and refurbished flats there is not normally a load on the floor. When the flat is occupied however, loading due to furniture, appliances, people etc, will occur which compresses the resilient layer if a floating floor construction has been used. The effect this has on impact sound insulation is considered in this paper. Impact sound transmission through a chipboard floating floor on battens supported on a concrete floor has been measured when static loads were placed on the chipboard – the loads were in the range 20 kg/m³ to 160 kg/m². Three different resilient layers under the battens were tested: 25 mm mineral wool quilt, resilient battens and resilient battens on 13 mm mineral wool quilt. The weighted standardised impact sound pressure level (L'_nTw) increased by 0.5 dB to 5 dB with the larger increases for the greater loads. Further measurements were made after the floating floors had been left under a static load of 200 kg/m² for six months: there was an additional increase in L'_nTwof 1.5 dB. Finally, measurements were compared with floors where the resilient layers had been soaked to simulate water leakage from baths, pipes etc; there was no significant difference in results.