Impact sound is a structure-borne sound that is generated for ex. by walking (foot traffic), moving furniture or knocking. The disturbing noise is mechanically transferred directly into the ceiling and radiated into the neighbouring rooms – mainly into the lower rooms.
Causes of impact sound deficiencies are mainly as follows: ceilings without floating screed, ribbed ceilings and solid ceilings with a too low mass per unit area, hollow core ceilings, unsuitable, too stiff or not weathering-resistant insulation layers and old wooden beam ceilings with slide-in floors.
Impact noise protection is defined as the protection against noise generated by mechanical stimulation of the raw ceiling, for ex. footsteps. If there is a lack of sufficient impact sound protection, the sound is increasingly transferred into the building structure and transmitted to the adjoining rooms as airborne sound.
In old buildings and for renovation works, there are often planning limits for the floor in terms of installation height and weight per unit area. In such cases, it is important to ensure maximum impact sound improvement with a minimum system construction height.
The standard DIN 4109 "Sound insulation in building constructions" specifies the requirements for impact sound and airborne sound insulation of buildings. It specifies a value (L'n,w) of ≤ 50 dB for flat partition ceilings in multifamily buildings. However, this value can only be met economically with the today commonly used solid-ceilings in combination with a floating screed.
More stringent requirements apply in upscale residential construction. Here, a corresponding construction height for the screed to be installed and a defined weight per unit area must be ensured.
Supplementary to DIN 4109, the guideline VDI 4100 "Sound Insulation in Buildings - Dwellings - Assessment and Proposals for Increased Sound Insulation" regulates the requirements for impact sound insulation of ceiling constructions in residential buildings according to different sound insulation levels.