Concertina doors are a general term used, in the UK and Australia most often, for a type of door that does not open outwards or inwards using of a hinge but instead folds vertically in one or more places, giving the appearance of a concertina, hence the name. By the way, concertina doors are called 'accordion doors' in the United States and elsewhere, which has mostly to do with what the musical instrument is referred to as in those countries.
A concertina door can be subidivided into multiple vertical subdivisions, depending on the width of the door and the application. But a common interior concertina door of standard width would have 7-10 vertical sections, though they can have as few as two (actually, these are called concertina folding doors). These are attached by some kind of pivot and can therefore fold alternately inwards and outwards, just like if you took a piece of paper and folded it vertically multiple times into strips, going first one way then the other, like a fan or, well, a concertina!
Concertina doors are usually fixed at one end, and this anchored vertical strip is in fact the only one to rotate out from the doorframe like a normal door.
The vertical section at the opposite end is the one which comes into contact with the other side of the doorframe and usually has some kind of catch which enables it to be closed all the way and stay put.
Some kind of mechanism is also needed for concertina doors to be able to glide easily open or
closed - if you can envisage it, each panel individually needs to slide freely left or right, as the 'concertina' is stacked open or closed. This aspect of the door can be vital, as a cheap, low quality track will not allow the door to slide as required, and the door will stick all the time
when used. Though this may seem trivial it can become a constant annoyance whereas a perfectly sliding mechanism will be a pleasure to use.
If you see concertina doors on sale for a low price, be aware that this may be exactly where they have reduced costs, and you may end up sorry you tried to save a few pennies.
They are used where a lightweight door is required to divide two areas of an apartment or other premises and in particular wherever there is too much of a premium on space to install a 'common-or-garden door that opens out. For this reason concertina doors can make a room appear much more spacious as the door itself does not fill up valuable space in the room.
Concertina doors appear in industrial and commercial contexts as well, of course, frequently in much larger form. Here they are frequently utilized to subdivide huge spaces - you have probably seen an aircraft hangar door take the form of a concertina door, where a normally opening door would probably not be a realistic option.
Also, if you attended a small school you might remember this kind of door being used to divide a single room into two groups of kids to try to provide at least some kind of separation and make the maximum use of a larger room.
To conclude, concertina doors are a practical solution for subdividing a premises and can be a fashionable solution on top.
Author Resource:
Find out more about concertina doors on Nigel Gundgeon's site and also read an article about the various types of interior doors for your home here .