What Are External Bifold Doors?

But exactly what is an external bifold door? Where can you use them? And how do they work? In this article, we'll answer these commonly asked questions among others, so that you can work out exactly why bifold doors are such a popular choice.

What Are External Bifold Doors?

A bifold door is made up of several panels, attached to one another via a series of alternating hinges. This arrangement allows the entire door to open and close in a concertina. External bifold doors separate the exterior from the interior and are seen at the rear of the property. They allow lots of natural light and air to flow freely into the home when the doors are open, making them a perfect addition for warmer months. External bifold doors tend to be used as a type of patio door.  The construction of your folding door will differ depending on where you're thinking of installing it. An external bifold door will need to be built in such a way that it can repel the elements. External bi-fold doors are commonly available in three different materials: timber bi-fold patio doors, uPVC bifold doors and aluminium bifold doors. Each material has its own advantages and disadvantages, so picking the right one is usually down to personal circumstances.

How Do External Bifold Patio Doors Work?

Bifold doors open by folding the door panels back on top of each other. They are mounted on a track and open by pushing the runners back together along the track. This means that when they are opened they can completely remove the barrier between your living space and your garden.

Do Bifold Doors Need a Track?

All bifold doors need a track for two reasons. Firstly, they'll need to be prevented from swinging all the way outward. Secondly, (and more importantly) the track bears the weight of the door and prevents excessive strain from being placed on the pivot pin. If you'd like to disguise your track, you can have it set into the floor. You might also elect to suspend your door from a ceiling-mounted track, thereby allowing the floor beneath the track to be seamless and uninterrupted. Whichever sort of track you choose, you'll want to keep it clean, lubricated and free from dirt. Apply some WD-40 every so often and run the door back and forth.

What Different Types of Bifold Door Are There?

When shopping for external bi-fold doors, you'll have three different formats to choose from. The first and simplest is to have a single long set of panels. This is known as an ‘x+0' configuration, where x is the number of panels. If you'd like easy access to the exterior without the need to open the bifold, you might opt for an ‘x+1' configuration, which incorporates a single door at the end, known as a traffic door. Through this door, you'll be able to move in and out of the building during winter, without allowing all of the warm air in your house to leave. If your set of bifolds is unusually large and doesn't have a handy alternative door nearby, then opting for a traffic door makes a great deal of sense. Finally, we have the ‘French-fold' variety, which incorporates two identical sets of panels which unfold from either side of the frame to meet in the middle. They combine the visual style of French doors with the spectacular size and looks of a set of bifolds.

What Size Are External Bifold Doors?

The construction of an external bifold door means that they can be made extremely large. Some are as wide as five metres. As such, they're able to replace entire walls, creating a seamless transition between the interior and exterior of a property when open. Aluminium, being stronger, can support a greater weight of glass, and thus it's what the really big bifold doors tend to be made from. The minimum size for folding patio doors tends to be around 1800mm. A door of this sort would consist of a trio of 570mm panels, which are the smallest variety available. As we move up into larger doors, the panels get wider and more numerous. You'll have a choice between a large number of narrow panels, or just a few extra-wide ones. A bifold door's maximum size is just under five metres.

What Height Are Bifold Doors?

For the most part, exterior bifold doors are as tall as any standard door in the UK, which is around 2090mm, or 2105mm for the frame. It's important to stick to millimetres when measuring your opening, as even the smallest gap around the edges can lead to considerable draughts. You'll need to account for a fitting tolerance of around ten millimetres when you measure up the opening.

Are Bifold Doors a Good Idea?

Given the popularity of bifold doors, you might be forgiven for thinking that they're a flash in the pan. However, their popularity endures, proving they bring a lot of benefits to any home.

Do Bifold Doors Add Value?

Bifold doors usually recoup their costs by immediately adding value to the home. If you show a prospective buyer around a kitchen/diner area or a lounge, then the sight of a stunning set of folding doors is certain to leave a lasting impression. The extra light they bring into a home can also change the feel of the indoor space to make it more enticing. It's difficult to estimate precisely how much value a set of external bifold doors will add to a property, but the effect will almost always be a positive one.

Are Bifold Doors Secure?

Just like all doors and windows, bifold doors can be incredibly secure or leave your home vulnerable, depending on the specification of the doors. Picking a set with toughened glass is one way to up their security, but laminated glass will make them even more secure. This is because laminated glass stays in place even when shattered making it the safest possible choice. That said, it is actually unlikely that potential intruders will try and break the glass to get through your doors anyway - it takes too much strength and makes too much noise. This means that getting a secure frame is the most important way to get secure doors. Make sure you get a high-quality set of bi-folds fitted with a multi-point locking system and you will get a secure set of doors that will keep unwanted visitors at bay while still filling your home with natural light.

Find out more in our detailed article, how secure are bifold doors?

Are Bifold Doors Energy Efficient?

As with security, bifold doors can be very energy efficient, depending on their specification. A set of aluminium doors with thermal breaks offer excellent energy efficiency. As do triple-glazed glass panels with a low e coating - even double-glazed panels with a coating are impressive insulators.

Are Bifold Doors Expensive?

Bifold doors are available at a range of price points, making them accessible across all budgets. If your budget is strict, then a set of double-glazed, uPVC doors offer completely satisfactory performance and visuals while still being easily affordable. In comparison, if you're looking for high-performance regardless of cost then aluminium external bi-folds with triple glazing and laminated glass offer incredible security, energy efficiency and stunning looks at an understandably higher cost.

To find out more, read our detailed guide on the cost of bifold doors. 

Can Bifold Doors Open Both Ways?

Bifold doors are a very flexible choice that can be configured to open any way you choose. However, if you have a definitive idea of how you want your doors open, it is best to buy a set made to that specification. Changing the set-up of external doors is slightly more difficult than internal ones, due to the level of security and energy efficiency they need to provide. Similarly, it is possible to reverse bifold doors but it is a lot easier to get a set that meets your requirements in the first place.

Are Bifold Doors Worth It?

We might be a little biased, but we genuinely believe that a brand-new set of bifold doors is a worthwhile investment. Not only do they connect your garden and your home as one seamless space, but their beautiful big glass panels and slim frames also create a visual centrepiece in themselves. And while they may not be the cheapest patio style out there, they can recoup some of their initial costs by increasing the value of your home too. External bifold doors are a popular means of opening up your interior space and connecting your home to your garden. Their construction allows them to be made larger than any other variety of doors, and thus they're capable of forming the ultimate visual centrepiece for your home and garden. Get an external one, and your summer barbeques will never be the same again!