Interior and exterior bifolding doors both use a simple tracking system that runs along the panels, which are connected on a train. The doors work by folding in on themselves and then gliding along the tracking system with the help of a series of wheels or a lower tracking system, which both lead to a smooth motion and quiet operation.

Bifold doors (particularly interior ones) generally come in pairs, with two doors folding to one side or with four that part in the centre with two doors folding back to either side. Your bifold doors will usually come with all tracking and fittings already installed, can be opened either inwards or outwards. It’s this kind of flexibility that has led to their popularity in recent years amongst open-minded homeowners. Most bifold doors will have anywhere between two and seven panels, all of which will be connected with hinges and attached to the roller track at the top or bottom of the door (or both). They are remarkably easy to operate, though it’s advised that you don’t get too carried away as if you use too much force you could end up pulling the doors out of the tracking system.


This is a particular concern for external bi-fold doors, especially amongst people who are not 100% sure about them. They can be very secure, though, more so, in fact, than most other types of external door (as we mentioned above), but the right measures need to be put in place to ensure this. You’ll want to make sure your exterior bifold doors have a decent locking system in place, which activates at multiple points instead of just one. You can also take measures to strengthen the glass of the door panels and the frames that support the doors. Reinforced glass is definitely a sensible option if security is a major concern for you. Finally, you could always install an alarm, giving you a little extra piece of mind. This will obviously prove costly, though.


The answer to this question can vary, but good quality, well-fitted bifold doors should not ever be too cold, though if your external bifolding doors are opened wide on a hot day, they can help to cool your home without resorting to expensive air conditioning or flimsy fans. The type of glass you choose will have a serious impact on the thermal efficiency of your doors. You could use energy efficient glass (with an R-value of at least 4.0), or use a special lining to maximise efficiency. Even if you don’t want to go to this extra effort, though, you shouldn’t need to worry about your external bifold doors letting in too much of the cold, because they are built to completely seal your home from the outside world, and are just as effective at doing so as conventional doors. Plus, the larger windows will spend all day letting the sun in, and if you then choose to adorn your doors with curtains or blinds at night, that heat should remain trapped.

Each different sliding door frame material will have varying properties too. Timber is often engineered to maximise thermal insulation and aluminium has a thermal break that helps keep heat transfer to a minimum. Bifold patio doors are also thoroughly tested for weather tightness.


Once you have selected the right door size, bifold doors are relatively easy to install for DIY experts. Whilst it’s not recommended for just anyone to attempt to install their own bifold doors, internal concertina doors will be much simpler to install than external ones because there is less to worry about with these door styles in terms of hardware. If you have some DIY knowledge and are confident in your abilities, you should be able to tackle the installation of an internal bifold door yourself, but we’d highly recommend seeking professional help if you’re looking into installing exterior bi fold doors.