A threshold is a relatively thin strip of material, usually wood or metal, that has beveled edges on each side. This threshold strip is used between two floors, in connecting them.
What this accomplishes is it makes the levels of the two floor areas more even, if they are uneven. The threshold is also used as a material that is common in color or style in joining the two floors, so that there will be a less noticeable difference in viewing the joined area.
Types of Threshold Material
Most threshold material is either wood or metal. Sometimes, however, plastic may be used as a threshold. This would be the case where it was desirable to have the softest threshold possible, for instance at the edge of a child’s room.
A wood or metal threshold could be something someone could stub their toe on, so care should be taken in the choice of a threshold used in a family home.