Described is a floor structure (1), comprising: a system of metal carrying beams (10) that are mutually substantially in parallel with a mutual intermediate space (11); resting on the carrying beams, a supporting layer (20) of a dovetail plates (21), with their longitudinal direction perpendicular to the carrying beams (10); a mortar floor (40) arranged on the supporting layer (20). In the intermediate spaces in between the carrying beams (10), a primary thermal insulation body (50) is arranged, closely fitting in between the carrying beams (10). Around the bottom part of a carrying beam (10), each time, a secondary thermal insulation body (60) is arranged, that abuts against the primary thermal insulation bodies (50) on both sides of the carrying beam.