Large knots, splits, cracks and any amount of sap- wood make hardwood a fun choice, and mean that your floor will be all that more distinctive. Knots occur naturally in wood where a branch grows out of the main trunk. They can go deep into the timber’s core. In terms of flooring, there are two types of knot. A dead knot is where the core of the knot has fallen out or been removed, and then filled. With a live knot, the core remains in the board.
The rustic and extra rustic grades contain both types of knots.