Aluminium and upvc bifolding doors are fully assembled in the factory although due to transport restrictions some larger doors are supplied with the outerframe in kit form for assembly on site. All doors can be supplied this way on request if you have limited site access. All timber doors are supplied in kit form and are assembled into the aperture.
Visit the Folding Doors 2 U website for more information on Are your doors supplied in kit form or fully assembled?