The surviving excavational data indicate that the Palace was floored with mosaic, marble, and brick.
It is the mosaics which best exemplify the artistic perception underlying the decoration of the whole complex. The compositional forms popular until the end of the 3rd century were now being abandoned, and geometrical decoration was preferred for the Palace floors, sometimes combined with vegetal motifs. There is a clear preference for compositions based on various kinds of meander, chequer-work (either as a border or as the main motif), octagons, and adjoining squares alongside lozenges. The individual motifs ornamenting the geometrical patterns which make up the representations are repeated in many parts of the Palace, either uniformly or with variations. Typical motifs include parallelepipeds, chainlike interlacing designs, open cubes, and egg-like ornaments with small darts interposed between them.