Automation, safety and load shedding
A new door should be commissioned with the automation, not have a motor added later as an afterthought. The motor is sized against the finished weight of the door including any glazing or timber, and the travel limits and force settings are set with the door already balanced.
Safety infrared beams across the opening are standard on every installation we do. So is battery backup — in this part of Johannesburg a motor without it means a door you cannot open when the power is out, which is exactly when you want to get a vehicle off the street.
The auto-reverse test is done in front of you: an obstruction placed under the closing door, the door striking it, and the door reversing. If it does not reverse cleanly, it is not finished.
Single, double and two singles
A double opening can take one wide door or two single doors, and the choice is not purely aesthetic. One double door is a single mechanism to maintain and a cleaner opening to drive through. Two singles mean one door can stay working while the other is repaired, and each door is lighter, which is gentler on springs and motors.
Where there is a central pillar you have no choice. Where there is not, the width of the opening and the weight of the finished door usually decide it — beyond about 5 metres, a single door starts asking a lot of its springs and its top section.
Measuring: headroom, side room and backroom
Three clearances decide whether a door can be fitted at all. Headroom is the distance from the top of the opening to the ceiling or the nearest obstruction. Side room is the space either side of the opening for the vertical tracks — usually around 90mm each side. Backroom is how far the horizontal tracks can run into the garage, which must exceed the door height plus the motor rail.
Obstructions are the usual surprise: a lintel, a lighting rail, a roller-shutter box from a previous door, a geyser, or a beam that crosses exactly where the tracks want to go. All of them have solutions; none of them has a solution that can be chosen from a photograph.