At present, the construction of detached houses and apartment houses widely uses beam ceilings, which mostly consist of wooden longitudinal supporting beams with off-set X-bracing on which a cover made OSB boards is fitted. On the cover there is a layer of cast concrete reinforced with a steel grid with a floating floor laid on top. A plasterboard soffit is hung on the undersides of the supporting beams under which a sound-absorbing layer of mineral wool is inlaid. A problem common to such structures is that measurements of the acoustic sound transmission of such ceilings show that these structures often do not meet the requirements of the relevant standard, and that noise from the floor above may reduce the comfort of flat-owners living below. It appears that such drawbacks are also often typical of the concrete ceilings of panel houses.
The new type of floor structure designed by the research team led by Doc. Novotný of the Institute of Building Structures at the Faculty of Civil Engineering, BUT, consists of a ceiling structure fitted with a floor structure which significantly reduces the above-mentioned disadvantages of the currently applied designs. Calculations for the acoustically-insulating characteristics of the newly designed structure achieve the values required by current Czech legislation. The technical solution to the floor structure introduces a ceiling structure fitted with a floor structure made of layers of footfall insulation and subsequently diffusion layers, the principle of which is that these layers are made of at least one layer of fibre-cement boards. Apartment houses place tougher requirements on acoustic insulation, therefore the ceiling structure is made by putting a flexible foil on the cover, followed by a layer of more than two fibre-cement boards on which a layer of footfall insulation is put, followed with another layer consisting of more than two fibre-cement slabs lying on top of each other. The wooden girders can also be provided with a lower cover which thus fulfils the static function of the transverse narrowing, while at the same time reducing acoustic bridges and the acoustic sound transmission of the ceiling. The cover can also be provided with plasterboard soffit with an inserted layer of mineral insulation.
The advantage of the new ceiling structure is that it substantially improves the acoustic properties of footfall noise and decreases air sound transmission in a particular structure. Another clear advantage of the system is the easy and low-cost assembly, as well the system’s functionality and not having to introduce a wet process into a dry building process.
Currently, the new type of floor structure is protected by the IPO CZ as a utility model, and an experimental building is being built in which the structure is to be tested and verified experimentally.
Source of main photo: Sarang, Wikimedia Commons, 2012.
