a process for the manufacturing of floor elements , which floor elements comprise an upper decorative surface and a lower surface , edges intended for joining and a core forming a carrying structure . a mixture of polyols , such as polyester or polyether , crude methylene diphenyl diisocyanate and possibly a small amount of blowing agent in a ratio forming a polymeric resin with a density in the range 600 - 1400 kg / m 3 is injected or cast into a mold , whereby a slightly porous or solid polyurethane core is formed . the polurethane core is , possibly after surface treatment such as sanding , provided with an upper decorative surface and possibly a lower counter surface