Structural requirements for overhead doors

May 20, 2021

When choosing an overhead door for a building, a number of aspects must be considered with regard to structural requirements, such as the mounting frames, floor details, installation and suspension facilities.

Mounting frames

An overhead door must be placed on an ‘auxiliary structure’ in the wall of the building. In doing so, it is important to take into account the desired materials and accompanying dimensions of these mounting frames, and to discuss this with the contractor or manufacturer at an early stage of the process. For example, a steel mounting frame requires a different minimum profile width than a concrete or wooden frame.

Floor details

If an overhead door does not lower completely to the floor surface due to uneven floor conditions, water may enter. It is therefore important that a water barrier, i.e. an offset, is integrated into the floor. The door is placed in front of the offset, which also slopes slightly. Because of this angle line, any water that enters will automatically run out again. If this kind of floor detail is not provided, water can enter the building, especially if the floor behind the door slopes downwards.

Installation

Cabling and power supply to the door must be taken into account when choosing an overhead door for a building. A 230V power supply can be used for a standard overhead door. If you opt for an overhead door in conjunction with a dock leveller, for example at a loading bay at a distribution centre, you must always use a 400V power supply. It is also important to determine early on, the side on which the control box should be placed, so that the contractor knows where the cabling must be routed.

Suspension devices

An overhead door is extremely space-saving. As the door swings upwards, there is plenty of space left and goods can be placed up to ten centimetres away from the door frame. In most cases, the overhead door swings inwards. This means that the horizontal tracks of the door must be hung in the roof plane, which sometimes requires the use of suspension devices.

The suspension devices depend, among other things, on the size of the door, the fitting – i.e. the rails and spring package – and the height of the roof. The latter determines the available headroom. If there is little headroom, the door will probably slide inwards directly above the clearance opening. In this case, extra low mounting or normal mounting is sufficient. If there is more headroom available, a highlift can be used. The door then first opens as far as possible along the facade and then turns inwards.

This offers several advantages: a more stable suspension is created, there is less risk of damage to the opened door and more space is available beneath the opened door. If there is enough headroom available, it is even possible to run the door vertically along the facade without the door swinging at all.

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