(guest post by Tony Cope)
Bifold doors have become very popular. They provide an ideal way of being able to close off or open up two adjoining rooms if the structural opening is too wide for a set of double doors. Usually the opening needs to be between 8 and 11-1/2 ft. (2.5 and 3.5 metres).
An alternative to bifolds would be a set of doubles and side screens (pictured below), but this doesn’t allow us to open up the total width of the opening. It can however, be fire rated if this is required.
For bifold doors, the hinges are very important because the system requires two doors to be hinged together. This will require three or four good quality steel hinges per bifold door, depending on their height and width. The doors that are hinged to the frame should have either good quality parliament hinges or projection hinges, which are a lot stronger. Since these hinges will be supporting the weight of two doors, the frames or jambs should be made of at least 32mm hardwood and definitely not softwood or MDF.
I also recommend to make the two inside doors slightly smaller by about 10mm on the width so that, when they are folded back, the inside doors don’t bind on the hinges.
The other issue is the handles. If you want the doors to fold flat against the outer doors and to fold flat against the wall, you may want to consider some kind of recessed handle.
Other ironmongery will include flush bolts on three of the doors with a latch or lock on the main opening door.
Note that the bifold configuration cannot be fire rated, because there is no test evidence this will hold up for 30 minutes in a fire.
Notes to author: Tony Cope is from Solid Wood Doors (SWD). With an established reputation for commitment to innovative design, unsurpassed craftsmanship and excellent client service, Solid Wooden Doors offers the best in manufacturing bespoke timber doors for residential and commercial purposes. www.solidwoodendoors.com or 01932 851081.