Tongue and groove are often used in conjunction with wood floorboards, sheet paneling, wainscot, and any number of other materials where a tight, solid seam is required between separate pieces. One tongue fits firmly into the groove of the adjoining board. The purpose is to control vertical movement between adjoining boards. Horizontal movement is still allowed to a small degree and, in fact, is a desirable quality, since wood flooring will expand and contract.
Advantages
Disadvantages
Tongue and Groove’s Cousin Lock and Fold
Basic tongue and groove joinery is a straight tongue that horizontally slides into a straight groove. To prevent the boards from moving, nails or flooring staples are driven into the tongues. These fasteners attach directly to the sub-floor. As laminate flooring manufacturers developed new ways of joining boards, a slightly different technique came about—floating floors. Floating floors attach only to themselves, from one board to the next, not the sub-floor. Luxury vinyl flooring capitalized on laminate’s innovations, and in many ways improved on them. At first, glue was used to join tongues to grooves. But an easier method, lock and fold, was developed to allow the tongues to fit into the grooves without glue or fasteners. Lock and fold involves angling one board onto the adjoining board and then folding it downward. This is significantly different from traditional tongue and groove in that horizontal movement, as well as vertical, is kept in check. There’s still room for some microscopic horizontal movement, but nowhere near the type of movement allowed by classic tongue and groove.
