Features and benefits of BI-FOLDS (BF):
You can use the active door to go in and out without opening the entire door,
You can open the entire space (generally opening outwards for correct sealing),
You can create large open spaces; generally opening up the room by 90%,
You can create the illusion of a larger home,
You can rebate the sill track or use a U-channel guide track to minimise the chance of tripping (water issues need to be considered with this type of installation).
A sashless double hung window can be placed inside the door sash to allow breeze in without opening the door