Bi-folding, bi fold, multi folding or sometimes called concertina doors create a 90% clear opening which turns your outside space into another usable room for the house or business. They are a fantastic alternative to French or patio doors which only offer a 40% opening. Express Bi-folding doors create endless opportunities for design and add a new dimension to your home or business. As an additional enhancement we recommend Uniblinds click here for more information. Transform two rooms into one, Extensive access to outdoor areas. Create alternative spaces for you home Maximize the space in your business for increased Profits.