Abstract: A modular flooring system having multiple modular flooring units and elongate spacer strips. The flooring units include a rigid base, tiles adhesively bonded to the base, and a frame affixed to the base and extending around the tiles to surround the tiles. The base of the flooring unit is substantially impermeable to moisture, and the frame may be made of a laterally compressible material such as wood for absorbing stresses. The tiles may be slate, granite, marble, ceramic or the like. Slots may be formed in the edges of the flooring units and the elongate spacer strips for receiving elongate splines to join the units and strips. The elongate strips may have a thickness substantially identical to the overall thickness of the flooring units, so that a plurality of elongate strips and flooring units may be joined to define a substantially co-planar floor surface. The strips and units may be provided in different sizes so that the dimensions of the flooring system may be varied.