FSC Standard Tongue and Groove Flooring 113 x 19mm (W x T), is manufactured from whitewood and designed for sub floor application. One side of the board has the ridge end protruding known as the tongue. The other side of the board is known as the grove. Tongue side of the board is fitted to the groove of the adjacent board, creating a snug beam. It is interconnected with each other, creating a neat and even flooring surface.