A floor board assembly convenient to lay is characterized in that, in one embodiment, it comprises a frame, a filler board and an upper material with the frame and filler board affixed to the underside of the upper material. The frame includes latch tongues that extend outwardly from the lower side edges of the frame, and the tongues have locking projections that fit into recesses arranged just inside the periphery of the underside of the frame. The tongues and intervening spaces (with locking bars behind them) are space along the periphery of the board, such that any side of one board may be joined to any side of a similarly configured board. The upper material may be selected from a variety of materials, including LVT (luxury vinyl tile), carpet, high pressure laminate or other decorative material. The filler board may be selected to accomplish reduced cost, and/or improved acoustics. In other embodiments, a frame and/or upper material may be absent. The floor board assembly requires a lower manufacture cost and lower equipment investment, has stable quality, versatility and ease of installation.