Impact noise from roof terrace - elastic ceiling in Sylomer hangers and free ceiling

Modern houses and apartments are built with flat roof and often the upper apartments contain a roof terrace. Impact noise has been measured from a roof terrace with floating floor on mineral wool, a good wooden construction with 2 layers of gypsum stiff fastened in the ceiling. This measurement shows L'n,w of 55 dB, and make it necessary with better solution for ceiling to achieve L'n,w 53 dB or better. Two measurements for improved situation in different buildings are done with ceiling in Sylomer hangers and with free ceiling. These two situations show L'n,w of 50 and 46 dB. The measurement of solution with free ceiling shows the lowest value of L'n,w for these two elastic solutions and also has the lowest levels in the low frequency range. This paper will show that for roof terrace the need for elastic or free ceiling is important. Concerning annoyance and low frequency noise, solution with free ceiling is to be preferred in future projects. There has been no complaining about impact noise from roof terrace, for the situation with free ceiling. For the situation with Sylomer hangers people living there hear some noise, but they have not complained about that.