WHAT DOES IT MEAN?
A roller garage door has a curtain of linked slats that travels vertically in side guides and rolls around a barrel above the entrance.
In practice
Because the curtain rolls up, it does not swing forwards onto the driveway. The roll, guides and motor still occupy space, so their position and dimensions need to be checked for the building and chosen model.
Roller doors vary in slat construction, operation, insulation, finish and protective devices. Compare the complete specification and the usable opening after installation rather than choosing by the mechanism alone. A made-to-measure door still needs suitable fixing surfaces and model-specific clearances.
