The smoothness of the underlayment is important because it affects what?

The smoothness of the underlayment is crucial because it directly impacts the finish appearance of the tile. A smooth underlayment provides a solid, uniform surface for tile installation. When the underlayment is uneven or rough, it can lead to tiles being laid at varying heights or angles, resulting in a visually unappealing surface. Additionally, imperfections can cause the tiles to crack or become dislodged over time, compromising the overall aesthetic and functional quality of the flooring. Therefore, ensuring a smooth underlayment is essential for achieving a polished and professional appearance in tile work. The other aspects mentioned, such as durability, installation cost, and adhesive types, can be influenced by underlayment quality, but the most immediate effect on aesthetics is related to the finish appearance of the tile.