How a sectional garage door works
A sectional door is a row of panels joined by hinges. B&D describes the panels running on tracks straight up and then across the garage ceiling, so the open door lies flat overhead instead of rolling up.
Panel lift is the same door by another name. B&D sells its sectional range as Panelift and Panelift Icon, and notes the type is also called a sliding, overhead or up and over door. It makes Panelift Icon up to 3.99m high and Panelift up to 3.415m, depending on the profile.
The weight hangs on a torsion spring assembly with lift cables and cable drums. Steel-Line calls a sectional door usually the largest moving piece of equipment in a home, and says its weight can approach or exceed 200kg.
The room a sectional door needs
| Minimum | Whose figure | |
|---|---|---|
| Headroom, standard install | 290mm | Steel-Line 2026 brochure |
| Headroom, low headroom front mount | 200mm | Steel-Line |
| Headroom, low headroom rear mount | 150mm | Steel-Line |
| Extra headroom when an opener is fitted | 50mm | Steel-Line |
| Side room, standard door | 125mm (Steel-Line), 120mm (B&D Panelift) | Each maker's guide |
| Depth inside, doors up to 2400mm high | 3374mm | B&D, with its ceiling opener and rail |
| Depth inside, doors 2401mm to 3000mm high | 4164mm | B&D, with its ceiling opener and rail |
Low ceilings, side room and depth
Each figure belongs to one maker and one set-up, so use the table to see whether a sectional door is likely to fit, then let the door specialist measure. B&D's side room grows to 140mm with its Smoothtrack wheels and 195mm with its Auto-Lock.
Depth is the one people forget. Once open, the panels and the opener rail run back along the ceiling, so storage racks, a loft hatch or a light fitting in that path all count. Merlin's Commander Ultimate opener is wall-mounted instead, which Merlin says frees up overhead space.
Insulation, high wind and bushfire options
B&D says insulation is available on all its sectional doors, and Steel-Line fits insulation into the back of the panels on its standard ones. The insulated garage doors page covers what it does.
For high wind areas B&D sells a Storm-Shield sectional door and a cyclone door called Windpanel. After Cyclone Yasi, the Cyclone Testing Station reported a significantly lower failure rate for sectional doors than for roller doors on similar homes.
On bushfire-prone land, B&D says its BAL-Maze seals for Panelift and Panelift Icon were tested by the CSIRO and performed up to BAL-40. Your BAL assessment and building surveyor still set what your home needs.
Looking after a sectional door
- Steel-Line's manual asks for preventive maintenance at least every six months, with the owner's share limited to lubrication and inspection.
- Keep oil and grease off the tracks; a light oil goes on the hinge points, roller stems and locks instead.
- Leave paint off every moving part: tracks, rollers, hinges, lift cables, springs and locks.
- A noisy door, or one that reverses on the way down, may only need its tracks and hinges cleaned. Steel-Line names brick dust from building work as a common cause.
- Book the service your warranty asks for: B&D wants one within the first 12 months, then at least once every two years.
Torsion springs and cables are not a DIY job
Steel-Line says the spring forces are about equal to the door's weight and are released violently if a wound spring breaks. Never loosen a fastener on the torsion spring assembly or the bottom cable fixtures. If a spring breaks, stop using the door and leave it to a door specialist.
What we would do
Stand in the garage with a tape measure before you order and check the depth as well as the headroom. B&D's figures put the open door and its ceiling opener rail more than three metres back from the opening, so mention any workbench, storage or loft ladder in that zone when you describe the job.