How a roller door works
B&D NZ describes a roller door as a ribbed steel curtain that rises and rolls onto a drum above the opening. Side tracks guide it and springs balance its weight, so a healthy door feels light to lift.
Dominator says those side tracks also stop its roller doors blowing open or shut, dropping or swinging. Its Series A door works by hand unless an Excel opener is fitted, and B&D NZ says an opener can go at either end of the drum.
The room a roller door needs
| Dominator Series A roller door | Dominator Flex-A-Door | |
|---|---|---|
| Headroom above the opening | 400mm | 80mm with its retractable head infill panel, 130mm with an opener |
| Sideroom beside the opening | 80mm, or 135mm with an opener | At least 100mm |
| Backspace | 450mm | Its springs sit inside the horizontal tracks |
| Sizes | Heights from 1300mm to 3200mm, widths from 1250mm to 3200mm | Made to fit the opening |
Not much room above the opening?
B&D NZ says roller doors suit openings with plenty of headroom, because the whole curtain winds up into a roll. Where the lintel sits close to the ceiling, the Flex-A-Door runs a roller curtain on a curved track instead, turning from upright to flat near the ceiling.
Dominator also sells the Flex-A-Door as a replacement for an old tilt door. Measure from the top of the opening to the ceiling and across to the nearest wall on each side before the door specialist rings, and they can tell you quickly which door fits.
Wind and salt air
Dominator says the pressed square-line profile on its Series A door helps cut how much the curtain bends under wind pressure. Ask about it if your garage faces the prevailing wind or sits on an exposed section.
Near the sea, salt is the bigger worry. As MBIE sets out NZS 3604, exposure Zone D covers homes within 500 m of the sea or a harbour, or within 100 m of a tidal estuary. Dominator's door warranty does not cover coating or base material damage caused by being close to the seafront, so the washing routine below matters more there.
Looking after a roller door
- Wash the curtain with clean water and a cloth. B&D NZ says every 14 days, including the parts the rain never reaches, and more often in salty air.
- Never put grease, oil or an oil-based spray such as WD-40 in the guides, B&D NZ says.
- Use powdered graphite, not oil, on a stiff lock.
- Check how the door runs every 6 months, and have it serviced every 12 months, sooner with heavy use or harsh weather.
- Keep the curtain and the steel finish in mind when you pick a door: Dominator makes the Series A in Zincalume or pre-painted steel.
Leave the springs to a door specialist
Dominator says the lifting springs are under extreme tension at all times and should only ever be adjusted by its trained dealers. If the door suddenly feels heavy, drops, or a cable looks frayed or rusty, stop using it and let a door specialist look at it.
What we would do
Check the springs before you buy a motor. B&D NZ gives 15kg as the most a roller door should take to move by hand, and Dominator suggests feeling how easily the door moves every three months. If yours feels heavier than that, ask the door specialist to look at the springs first.