Perhaps considered the most basic door type available, the flush door is one that has no stiles, rails, or panels. In other words, the surface of the door is smooth. These doors can be constructed of solid or hollow wood, or even metal. Flush doors are commonly used as interior doors in homes, and they are known more for their functionality than their aesthetic appeal. Flush doors are simple interior doors that feature plain facings on both sides of the construction. While this type of door is more closely associated with function rather than style, this plain sort of door lends itself well to a number of room designs where the desire is to highlight other elements in the space. Doors of this type may have a solid or hollow core. The typical flush door is manufactured by using two sections of plywood that are attached to each side of a frame. While the interior of the door is hollow, it is not unusual for some sort of support to be built into the frame, such as a honeycomb support system.
It is also possible to construct flush doors using a solid core piece that is augmented with some type of laminate or plywood on each side. As with the hollow door design, the solid model is then painted or stained, then treated to a sealant. While heavier than the hollow versions, the solid flush door is often a better option when installing a flush sliding door at a passage between two rooms.