Bi-folding doors are an on trend way of increasing the width of a walkway. Glazed French doors, since they are hinged on either side, can only offer double width opening. A bi-folding door can increase the width of an opening because the doors zig zag onto themselves, concertina fashion. They also take up less space when they are open. Although modern materials mean that larger bi-folding doors, that house big glazing sections, are possible, bi-folding doors have been used in architecture since ancient times.
The No-Wall Wall.
A living room can feel like a stunningly different space if one wall is given over entirely to a bi-folding door, making it the perfect space in summer.