Dense-ribbed wooden ceilings are ceilings made of wooden beams (called ribs) with a short wheelbase, thanks to which they carry light loads and can have small dimensions. They are most often made of boards with a thickness 3,2 – 5 cm and properly selected height. Depending on the needs, stiffening concentrations of the ceiling are used, which prevent excessive deflection and twisting of beams.

If the spacing of the walls is large enough, that ribs based on them would have too much span (which could lead to excessive deflection of the ceiling), beam-ribbed ceilings can be used, where the ribs of the ceiling are supported on more massive ceiling beams acting as substrings. This solution increases the thickness of the ceiling, which is the sum of the heights of the ribs and pull-ups. To avoid this, instead of resting the ribs on the hoists, they can be mounted from above between the strings (Ie. hang to them with steel hangers). The dimensions and spacing of the lifts depend on the load on the ceiling. Pull-ups can be wooden or steel. Wooden pull-ups have rectangular cross-sections (from one or more compacted boards) or I-beam (with a structure similar to ribs) Steel pull-ups are most often made of rolled I-beams.

On the string beams and ribs, the structural layer of the floor is laid, so-called. Sheathing (sometimes called blind floor). Only on the sheathing the right floor is laid (floorboards, parquet, Mosaic, Panels). In ceilings above damp rooms, such as kitchen and bathroom, above the basement or ground floor in a building without a basement, waterproof boards are used as a sheathing.