Distribution ribs in multi-rib ceilings are perpendicular to the floor beams. They prevent the ceiling from "clinging" and ensure the cooperation of the beams in transferring loads.
• Do 3,0 m of span, separating ribs are not used.
• Od 3,0 do 4,5 m it is recommended to use one separating rib.
• Od 4,0 do 6,0 m, two separating ribs are used.
Separating ribs are made by spreading the floor hollow bricks to a distance equal to the width of the rib, That is 7 – 10 cm (formwork is made under the spread hollow bricks). The distribution rib is reinforced with two steel rods with a diameter of 10-12 mm, connected what 30 cm with S-shaped wire stirrups 4,5-6 mm. Reinforcement bars of the distribution rib are anchored in tie beams parallel to the system of floor beams. Separating ribs as an important structural element of the floor should be taken into account in structural calculations.
The connection of the slab ceiling with the ribbed ceiling is often between the staircase and the apartment. Due to the difference in the height of the reinforced concrete floor slab and the slab ceiling, there is a difference in the height of the ceiling, which increases even more due to the different heights of the finishing layers of the floor. In the staircase, the finish of the raw ceiling is usually adhesive mortar and ceramic tiles. On the other hand, in the apartment the most common solution is the so-called. floating floor, i.e. a layer of concrete screed on thermal insulation boards and finishing – e.g.. wooden parquet.