Single-layer steel sections
That means single-layer steel sections, sometimes still on the narrower single-car openings that were standard for the tract homes built through here, with a two-car garage being the exception rather than the rule. The hardware is older too: torsion springs sized for a lighter door, extension springs on side rails in the older single-bay setups, and openers that have been swapped out once or twice over sixty years but still bolt to framing that was never squared for anything heavier.
