Bi-fold doors commonly have outer materials of rustic hardboard, wood veneer, molded panels, paint or medium-density fiberboard. Their core materials may be agrifiber, wood-based particleboard core, hollow core or commercial hollow core. Bi-fold doors are also available with a variety of possible inserts such as mirrors, louvers and decorative glass.
Bi-fold doors consist of two narrow door panels that are hinged together and aligned by an overhead track. Regular openings generally use two door panels, and larger openings generally use four door panels that part to the sides so the center is wide open. Bi-fold doors can be tailored to a variety of opening sizes.
Bi-fold doors are often used in areas that have little extra space, such as passageways, closets, laundry rooms and pantries. They can be very practical because they enable access to large openings without taking up much floor space. Bi-fold doors have less material that gets in the way in comparison to regularly-hinged doors.
Bi-fold doors can be difficult for an individual to install. The alignment of the hinges, pivots and track require great precision for successful installation.
As of 2015, basic bi-fold doors can be purchased for under $50, while high-quality bi-fold doors can cost several hundred dollars.