Folding Door Glossary & Terminology

Get up to speed with the industry terms!

What is the bifolds ‘sightline’
When you look at a set of bifolding doors, the distance between one glass panel on one door leaf to the next is called the sightline. Another way of thinking about it is that it’s the full width of two of the door frames. Often, the sightline is incorrectly perceived as the frame width. The sightline on our NW1 bifold system is an incredible 120mm – one of the slimmest available in the UK. One of the key benefits of folding aluminium doors is that they have slim sightlines compared to alternative materials. This allows more natural light into the home and less frame in the interiors view of the exterior which creates a contemporary open look and feel.

Door Hinge
Hinge used to hang an aluminium door panel in a frame

Bifold Hinge

Used to attach two or more folding panels together

RAL Colours
RAL is the industries leading colour matching system. It allows you to specify an exact colour from the RAL colour range for us to perfectly match when we powdercoat your bi-fold door frame.

The method of removing water from the frame sill and panel

The cill
The cill is the bottom part of the door that projects out. A cill is there to channel rainwater away from the brickwork underneath.

A jamb

The door jambs (often known as the door-posts) are the vertical sections of the door frame/structure. It’s important that the jambs have a solid wall to fix to. Depending on the configuration, bifolds can have many jambs. A portion of the door’s weight is taken up by the top and bottom tracks, but low quality door systems or poor fitting jambs can lead to the frame twisting and flexing.

We are adding to this section all the time – however if you don’t see the word or phrase in our handy glossary, then feel free to get in touch with our helpful team who will be happy to help.