Hardwood timber floors look great and last for decades. One of their few disadvantages is that they will not soundproof the floor. A hardwood floor upstairs will transfer sound to the rooms below.
Floating floors are most commonly installed for either heat insulation purposes or for soundproofing. The materials used between the floating floor and the main floor below will determine how well these functions are performed. Many types of between floor insulation are good for thermal insulation, some are also good for acoustic insulation.
Sound will be dampened when it has to travel through different mediums. A combination of dense and loose materials will provide at least some sound attenuation.
Sand would be very effective for sound insulation, but the weight makes it unsuitable for upper floors. Acoustic fibreglass is used by some installers, but people often avoid fibreglass when building.
Rubber matting is a more common option for soundproofing floors. It can greatly reduce the sound of people walking on flooring made of wood, which is be far the greatest problem experienced by people in floors downstairs. 30 decibels of noise reduction is a reasonable expectation for rubber matting under a floating timber floor.
Carpet and rugs will significantly reduce the noise of people waking on floors, but this means covering up the timber. This is undesirable in many situations, such as dance studios where a hard floor is required.
Sound proofing prevents sounds from one room being heard in an adjacent room. This is distinct from acoustic absorption (sound absorption) which reduces the echo of sound inside a room. Methods of soundproofing may have a moderate effect on sound absorption in a room, but sound absorption is quite a different goal to soundproofing.
Timber flooring is great for so many home and business buildings. Floating floors allow us to keep the timber floors while reducing the noise heard in rooms downstairs.