Base moulding is an important part of any moulding package. It is generally the horizontal board that runs along the floor of your home used for both a visual and functional purpose. As for it's visual purpose, base is used to hide any unevenness the wall and floor joint. For functional purposes, it seals the wall and floor joint, and covers any expansion gaps needed for your flooring to properly expand and contract due to humidity, temperature, and the settling of your home. It also helps protect your walls from kicks, abrasion, and furniture.