What is T & G Flooring?

- May 23, 2019-

By Philip Schmidt

Tongue-and-groove flooring is made up of individual boards with special interlocking edges that are hidden once the boards are installed in the finished surface. Each piece has a tongue (a continuous ridge or tab) along one side and one end of the board and a groove (a channel) along the other side edge and end. The grooves of each piece fit over the tongues of the neighboring pieces, locking the pieces together so the boards stay flat and resist movement. The quintessential tongue-and-groove flooring material is solid hardwood planks, but there are several other types of wood flooring (and even vinyl) that fall into this category. 

Installing Tongue-and-Groove Flooring

Tongue-and-groove flooring can be installed with several different methods. Solid-wood and most engineered planks can be fastened to wood subflooring with nails. This involves a special technique called blind-nailing, in which flooring nails or staples are driven at an angle through the tongue edge of each plank, angling backward toward the plank. When the next row of planks is installed, their grooves fit over the nailed tongues, hiding the nail heads. Nailed tongue-and-groove flooring typically is installed over a layer of rosin paper or building paper and is fastened with a flooring nailer or staple gun.

Installation with glue (flooring adhesive) is an option with solid-wood, engineered, laminate and tile-type tongue-and-groove flooring. Glue is often used to install flooring over concrete slabs because the concrete is difficult to nail into. However, glue installation is not very DIY-friendly and is not necessary for most residential applications.

An easy alternative to glue-down and nailed installations is a floating floor, which uses no glue or fasteners. This is the preferred method for DIYers and works with laminate and some types of engineered and vinyl flooring. The installation starts with an underlayment of thin foam or other material (this isn't typically used with vinyl) that's laid over the entire floor. The flooring planks are laid row-by-row (as with nailed and glue-down installations) and the planks are joined together by fitting each new piece at an angle against the installed row, then pressing the new piece flat, interlocking the special tongue-and-groove joint. After each piece is laid, it is usually tapped tight against its neighbors with a special block (to prevent damage to the tongue edge) and a hammer or mallet.