A flush door is a completely smooth wooden door, having plywood or Medium Density Fiberboard fixed over timber frame which is comparatively light. The hollow core so obtained is often filled with a cardboard core material. Flush doors are most commonly employed in the interior of a dwelling, although with some variations they are also used as exterior doors in houses. The frames for such wooden doors can be made out of wood, steel etc, which can hold its weight. The doors are usually hinged along one side to allow the door to open in one direction only. Flush doors are commonly provided in houses these days due to the reasons of economy, pleasing appearance, durability etc and are commonly available in the market.