Engineered and laminate flooring will need an underlay. Because these flooring types are “floating,” there will always be a slight space between the flooring and the subfloor. Underlay minimizes these gaps, as well as helps with subfloor imperfections, prevents uneven or unstable flooring, and minimizes hollow sounds when walking on the floor. Some laminate flooring comes with pre-attached foam – these do not require underlay. Hardwood flooring, vinyl flooring and carpet tiles that are bonded directly to the subfloor do not require an underlay.