French windows / doors are limited in the overall width of the opening and sliding doors usually offer only about half of the available opening space.
PVCu, timber and aluminium are the typical materials used to manufacture bifold doors and each has its advantages over the other choices when it comes to colour, looks and feel, and durability. All, however, are fitted with either double or triple glazing to provide the very best in thermal performance and security.
Often, photos mislead viewers into believing that a simple exterior drain and a flush floor will provide a smooth transition from inside to out without compromising the doors’ effectiveness. However, to resist water penetration a raised threshold is all but essential except in particular circumstances where there is a solid cover or canopy to the exterior.
Although a flush floor to the outside is highly desirable it is not effective in the winter when it comes to keeping out the draughts.
Bi-fold doors offer excellent access and truly open up a new way of enjoying the great outdoors, but it is important to ensure that the threshold also provide a solid sealed wall to the less desirable elements such as rain and cold.