Tongue and groove flooring was first developed in the late 1800s. It was developed in order to eliminate the need for exposed nail heads on the top of each board. Now, tongue and groove flooring is not exclusively hardwood but also has engineered and laminate options. Although these planks interlock together, they still need to be nailed to the sub floor. To prevent squeaks, first lay a sound absorbing underlayment. For hardwood options, a flooring nailer can attach each plank to the sub floor. Engineered floors lock together.
Read more: Tongue and Groove Flooring 101