4-panel bifold doors, made to measure

This bifold door puts two door panels side by side, opening to either side as a pair — wider than the single traffic door of the 3-panel bifold door — with two panels beside them that fold away. For a bit more than an ordinary way through, such as carrying a large garden chair or a table outside, the pair of doors already gives more room than a single traffic door, without opening up the whole set.

The standard size is 3,600 × 2,300 mm, up to 4.00 m wide. If you need more width still, the 5-panel and 6-panel bifold doors are the wider next steps.

The pair of doors is the first point in our bifold range where the way through itself gets wider than an ordinary door: two panels of around 900 mm each give almost two metres of clear opening with both open, against the 800-odd mm of a single traffic door on the 3-panel bifold door. That is just enough to carry something bigger than a person outside without moving the folding panels.

Four metres is also the width where the difference between a single and a double door pays off most: on a narrower set such as the 3-panel bifold door, a pair of doors takes up too much of the total width, while on this and the wider bifold doors it becomes a smaller share of the whole.

For this bifold door, measure the width and height of the opening, the reveal the stack of folding panels will stand against, and the floor build-up under the track. The pair of doors needs its own threshold detail, just like an ordinary door — have your installer confirm how it meets the floor before you order.

Colour and finish are usually the same across the whole set, pair of doors included, for a continuous look. Maintenance is split between the two door panels, which are used most and so wear most, and the folding hinges and bottom track of the two folding panels, which move less often but must be kept clear of dirt to fold smoothly.

When renovating a wide rear wall, this is often the replacement for an older patio door or a row of separate windows, with the pair of doors as a practical advantage over a single traffic door in everyday use. In a new build, this size is often chosen when the room behind is large enough to make use of the full four metres once the set is fully open.

For security, the pair of doors has two locks that both need attention, including the door you rarely open; the folding panels lock through the locking points at each panel joint. Ask about the standard specification of both if the set is going on the ground floor.

The two door panels carry their weight on their own hinges, separate from the folding hinges of the two folding panels. The configurator checks for each panel whether the hardware suits the profile and the size.

Still not sure? Use the comparison with the other layouts in this group, above, to see which arrangement suits your situation best.