Bi-overlay entryways are a well-known decision while hoping to expand space and light. The concertina configuration can in a real sense open up a whole mass of glass, interfacing within to the outside with a level limit. At the point when shut, the scope of glass offers a lot greater perspective in contrast with a standard window or entryway. In more modest properties, bi-folds will give the deception of the room as your eye goes on past the rear of the house.