What a sectional door is, and why it is the common choice
A sectional garage door is four or five horizontal panels, hinged along their length, that lift straight up and then back along tracks on the garage ceiling. Because the door goes up rather than out, a car can be parked right against it and it still opens. That single fact is why sectionals have become the default new installation across Cape Town: driveways are short, garages face the street, and a door that needs a car's length of clearance in front of it is a door that gets left open.
The panels are steel, insulated or not, in a range of pressed profiles and colours, and because they are separate a damaged one can be replaced on its own rather than the whole door. Double doors are a single wide sectional rather than two singles, which is what makes them the standard on the double garages of the Northern Suburbs. The door is counterbalanced by torsion springs on a shaft above the opening, and it is these — not the motor — that carry its weight.
What a sectional needs from the garage
Headroom. A sectional needs space above the opening for the tracks to curve and for the spring shaft, and space back into the garage for the door to lie flat when open. Standard fittings want somewhere over three hundred millimetres above the opening and the door's own height plus a margin in depth. Low-headroom track kits exist and bring the requirement down considerably, but a garage with almost nothing above the opening — a City Bowl garage cut into a slope, a converted carport — may be a roll-up garage rather than a sectional one, and that is a measurement rather than an opinion.
Side room, for the vertical tracks either side of the opening. A sound lintel, because the spring shaft and its brackets carry the door's weight into the wall above. And a ceiling or roof structure that can take the horizontal tracks and, in most fits, the motor. All of it is checked on the measuring visit, and installation is quoted for the door the garage can actually take.
Insulated or not
A sectional panel is either a single steel skin or a sandwich of steel around an insulating core, and the choice is about what is on the other side of the garage. A detached garage that holds a car and nothing else does not need insulation. A garage under a bedroom, beside a living room, or converted into a workshop or a gym does, and the difference in summer heat and winter cold through a single-skin door is enough to notice from inside the house. Insulated panels are also stiffer, quieter in wind, and dent less easily — which matters on a door that faces the street.
On the coast the choice tilts further. An insulated panel has two steel skins to corrode instead of one, and the sandwich edge is where salt gets in, so a coastal sectional is specified with a properly sealed panel edge and stainless hardware, or it is a single-skin door with a coating rated for the exposure. Which is right depends on how close to the sea it is, and it is a conversation on the measuring visit rather than a default.
The motor for a sectional
Sectionals take any of the three drive types — chain, belt or screw — on a rail along the ceiling, and the choice follows the garage: belt under a bedroom for quiet, chain on a detached garage, screw on a heavy door away from dust. The motor is sized for the door's weight and the household's use, and a double sectional on a family driveway needs a motor rated well above the cheapest one that will move it. Garage door automation sets out the sizing; the short version is that a motor chosen for price on a double door fails at year three.
Beam sensors, force limits set to reverse against a hand, and two rolling-code remotes are fitted and set with every motor.
Living with a sectional
A sectional is the lowest-maintenance of the three door types, but not maintenance-free. The rollers want a check and a lubricant once a year; the torsion springs last roughly ten thousand cycles and are replaced rather than repaired when they go; the hinges between panels work loose over years and are tightened. On a coastal door the bottom panel and the hinge line are checked for rust every year or two, because a bottom panel caught at the bubbling stage is a panel, and one caught at the hole stage is a panel plus a hinge line plus a crooked door.
The thing that ends a sectional early is neglect of the balance. A door that has become heavy and is being lifted by its motor rather than its springs burns the motor out, and the fix — a spring rewind or replacement — costs a fraction of the motor it saves.