A removable modular slab for use in the construction industry includes an upper surface, a lower surface, first and second opposing end surfaces, and a conduit extending from an aperture in the upper surface to an aperture in an end surface. The slab is end-to-end abuttable with a second removable modular slab, having: (i) a conduit extending from an aperture in the upper surface to an aperture in an end surface, and/or (ii) a cavity extending from an aperture in an end surface into the slab, whereby the conduits are mateable so as to form an elongate conduit through the two slabs. Such elongate conduit is accessible through the apertures in the upper surfaces of each slab. By such access, a first joining structure is removably locatable to join the two slabs together. Cavities may terminate within the second slab and only be accessible through the aperture in the upper surface of the first slab, into which a joining structure is removably locatable to join the two slabs together. A modular surface system includes two such slabs and a joining structure to join the two slabs together.

Prefabricated floor element (1) having an elongated shape wherein a longitudinal direction (X), a transversal direction (Y), a height direction (Z), two end faces (11) which delimitate the element (1) in the longitudinal direction (X), two lateral faces (12) which delimitate the element (1) in the transversal direction (Y), a lower face (13) and an upper planar face (14) that delimitate the element (1) in the height direction (Z) are defined, which comprises transversal continuous upper grooves (15) on the upper planar face (14) or lateral grooves (26) on the lateral faces (24), the lateral grooves (26) extending from the lower tab (TS) to the upper planar face (24). The invention also relates to a structure comprising such prefabricated floor element (1) and further comprising a linear supporting element (LS) which supports one end of the prefabricated floor element.