Different types of folding doors

Folding doors come in many configurations

Choosing a type of folding door for the home or office can be a problem if you don't know the difference between a bifold and a sliding fold door.
In recent years, all types of folding doors have become very popular with homeowners thanks to their versatility and ease of use.
Bifold doors, also called folding sliding doors, can open inwards or outwards and can include a standard door at one end. Interior bifolds can act as room dividers, while exterior doors can open up a whole wall.
They can be manufactured in various materials and multiple sizes with an array of optional extras, which is why they have become popular features of many homes and offices.
Exterior bi-folds are a great way to bring more natural light into a room and 'extend' space into the garden or patio area. However, the range and the options can be bewildering, so it is a good idea to start with the basics and learn about the different types, how they function, and what is required for a successful installation.
We look at each type, in turn, to help you decide which type of folding door is best for you and your home or office.

Bifold door costs

Bi-folding doors can come in a wide range of sizes. The larger bi-folds are often used to split rooms or connect smaller ones. Bifolds come in many styles and configurations, indoor and outdoor, as well as single-leaf concertina or multi-leaf room dividers, so it's helpful to know what each has to offer. The cost of installing a bifold door will vary depending on the size of the installation, the specification of manufacturing materials, and the door system's configuration. As a rough guide, and for a high-quality installation, you can expect to pay £1,200 to £1,500 per linear metre of frame opening with added VAT and installation costs to be added. Off-the-shelf systems will be cheaper and have shorter lead times, while bespoke installations will cost more and take longer to arrive. Installers usually ask for plenty of details before offering a quote to ensure an accurate price and the installation that best meets your needs.

Concertina doors

Concertina doors or single bi-folds are the smallest of the bi-fold door ranges. They consist of two hinged panels and are an alternative to a single or double-door frame. Unlike a single door hinged to the frame and swings in or out in an arc, the concertina door folds up on itself and, when fully open, sits flat against the frame or wall. The arc is much reduced with a single opening, and the single concertina door is perfect where internal space is at a premium. Examples of where a concertina door can be useful are small bathrooms and built-in wardrobes or similar closets. Some concertinas can have two door-sized panels to fit a double-door frame. Again, the advantage is space-saving as there is no double arc opening as with conventional double doors.

Room dividers

The name bi-folds can give the impression that only two panels are possible, but the number of hinged panels can be increased substantially. It is possible to have a bifold with seven or eight panels that open and close in the same 'concertina' fashion as a single bi-fold. Again, they come in various configurations, but the most important are those with or without a separate access door. The standard room divider bi-folds operate the same way as a single bifold, but the panels are hung to run along tracks that keep them stable when opened or closed. As the door is opened, the panels slide over each other and stack against the frame or wall. There can be an even or odd number of panels; it doesn't usually matter as long as they fill the space. With an even number of panels, there is the option of opening them from the middle, with one set sliding to the left and the other to the right. The greater the number of panels, the deeper the profile when they are all stacked open, so bi-folds opening left and right may be a better option.

Bifold access doors

Not everyone wants to open all the panels in a bifold door each time it is used. This is why multi-panel bi-folds often include a single door on one side. This access door has the advantage of opening as usual, so moving between rooms is much more convenient. The single panel operates like a standard door, opening independently to the others, which concertina together as you would expect. Access doors can be fitted to the right or left of the bifold panels to match your preferred position.

Interior and exterior bifolds

Bifold doors can be used internally as room dividers or externally to provide access to a patio or garden. Most exterior bifolds are made of glass with frames of uPVC, composite wood, or aluminium. Large glass panels raise issues of thermal efficiency, but most modern designs come with double-glazed panels and energy-efficient coatings. Exterior bifolds need solid and efficient seals to make them weatherproof all year round and good security locks to keep out unwanted intruders.

Bifold door materials

The choice of material is a personal matter, and much depends on individual taste. In terms of price, the cheapest option will be bifold doors made of uPVC. Many people were put off by the thick, chunky profiles of uPVC, but technological advances have resulted in a much more slimline appearance. A restricted range of colours also used to be a problem, but modern uPVC doors now come in a wide range of colours and finishes. Aluminium bi-fold doors are more expensive than uPVC but have several advantages. As easy to clean and maintain as uPVC, they combine strength and low weight to allow wide panel widths and ultra-thin profiles. Available in a wide range of durable powder-coated colours and finishes. Wooden bi-folds tend to be the most expensive and are usually made of factory-finished engineered hardwood to prevent warping or twisting. They can be painted in almost any colour, but many prefer a stained finish in oak, mahogany or teak.

More on sliding and bi-fold doors

Sliding doors versus bi-folding
Colours for aluminium bi-folds
How sliding doors work