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 Up to the 1970s the closing of large building openings was mostly realized by either folding doors or the “more modern”, electrically operated rolling doors.
Through the development of the sectional door of which the weight was counterbalanced by torsion springs and thus obtained the possibility of a better insulation, the previously established door technology was more and more driven out of the market.
Due to the oil crisis and rising energy prices, the badly insulated steel folding doors with their furthermore dangerous pinch points at the leaf edges had to make way for the sectional doors more and more often.
It is through the adaptation of profile systems used in sectional doors to the folding door construction in connection with highly insulated fillings and the use of accident protection profiles including a large rubber sealing between the leafs, that the folding door experiences a rebirth.
Used in Industry
 In contrast to the heavy, mostly entirely closed steel folding doors of the past, modern folding doors offer natural lighting, a filigree design, a high thermal insulation as well as highest functionality. Besides, they do not need much space at the sides and in the lintel.
Used in Hangars
 By the arrangement of the leafs to one another, there is theoretically no limit to the width of a folding door. It is merely the mass of the door leaf, which rises along with a growing door surface, that restricts the size in practice.
Nevertheless, our smoothly running rolling gadgets allow the operation of a door measured 20 m width and 4 m height. This size already covers a major part of the necessary dimensions in sports aviation. The required running track on the ground can be easily passed by sports aeroplanes.
Also the possibility of a traffic leaf, which can be integrated into the door leaf, offers an advantage, because only one leaf has to be opened if the necessity arises.
Used in Washing-Bays
Especially in washing-bays the folding door offers outstanding advantages:
- No dripping (of water) off the door on the washed and dried vehicle
- No danger of collision of the door and the washing unit
- Possibility of glass double glazing ensures better noise insulation and better cleaning conditions than synthetic glazing
- Exterior drive technology makes the door less accident sensitive
Used In Underground Car Parks
Even in modern underground car parks the problem of too low lintels appears more and more often. It is for financial reasons that underground car parks constantly become lower and the space for door technology tends to zero in more and more cases.
The question is whether it really makes sense to mould a notch into a concrete ceiling in order to maybe fit in a rolling grille or to build the whole park deck 10 centimetres higher and thus provide enough space for a sectional door.
With only little lintel requirements and due to the elimination of the legally regulated pull-in security device in the form of internal and external light barriers (which frequently fall victim to vandalism and thus often lead to damages of the whole door facility) the folding door with its manifold possibilities of filling designs (expanded metal, perforated metal plate, stick-type grid filling) represents a welcome alternative to the door types that were so far available.
Apart from the above-mentioned minimum requirements, the only precondition for the installation of a folding consists in a level ground or a sloping ground in the area of the opening.
Replacement of old doors
When exchanging 30-year old doors for example, we are often faced with cramped installation conditions, because at this time the sectional door was rather unknown and all architects proceeded on the assumption that the door would require the space of a folding door.
Apart from that crane rails often represent an obstacle for sectional doors, because the existing space conditions do not allow the installation of that door type.
Example of a minimum need for space: folding door opening 90°, 4 leafs
Right / left door stop: 110 mm
Lintel requirement: 190 mm
before
afterwards
The Special Door „Music Shell“ on the Island of Juist
 Due to the aggressive sea air all the attachments were bored in advance and powder coated.
Again minimal installation dimensions required the use of a folding door. Furthermore, the impressive visual effect of the “music shell” was not to be spoilt by running rails, which become visible when the door is open.
A planned side effect was the fact that the open folded leafs canalize the sound and thus support the architectural acoustic concept of the building.
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