TERIVA 4,0/1 ceiling with length of more than 6,0 m and created with assumed outline of partially-installed joist is an exception – proper installation conditions are achieved when the ceiling is designed as at least two-span one, at neighbouring spans ratio of value not less than 0,7.
According to PN-B-03264:2002 norm: the construction supporting reinforcement should be applied in every kind of multi-rib ceiling.
The ceilings with a span given in the table require creating a reverse ceiling deflection (upwards bending in relation to ceiling constant suports) by 15 mm. The length of beams embedment on the fixed stand (wall, downstand beam) cannot be less than 80 mm. In case of residential construction ceilings it is recommended to apply higher and more rigid ceilings, especially where there is no need of creating a reverse ceiling deflection. This is because with the application of such kind of ceilings – the occurence of possible partition walls and plastering damages is less likely to appear than in case of more flexible (lower) ones.