Sound insulation of walls using wood insulation mat and plywood jointed with a combination of adhesive tape and wood dowels

In this study sound insulation of walls was evaluated using wood insulation mat and plywood jointed with a combination of adhesive tape and wood dowels. Building of actual wall assembly test specimens and evaluating their sound insulation revealed that the sound transmission loss for jointing using a combination of adhesive tape and wood dowels was considerably higher than that using nails, for middle and high frequency ranges of 2 kHz and above. When comparing heat-insulating materials (sound-absorbing materials), the test specimen using high-density glass wool had greater sound insulation than the specimen using low-density materials, and the specimen using wooden heat-insulating/sound-absorbing materials showed roughly the same properties as glass wool of 20 % higher density. When the sound insulation for impact sounds of the experimental specimen (joined with adhesive tape and using wooden heat-insulating/sound-absorbing materials) was compared to a specimen with a typical composition (joined with nails and using glass wool), the former proved to have better sound insulation, by approximately 10 dB for light impact sounds between 400 and 800 Hz and approximately 5 dB for higher frequencies. For heavy impact sounds, the experimental specimen displayed a greater sound insulation for all frequencies, by 5–10 dB at frequencies of around 100 Hz and of 400 Hz and above.