Rolling steel door repair

Curtain damage, almost always from an impact. A forklift or truck catches the bottom bar or a slat, and the curtain no longer tracks straight in the guides. Individual slats are replaceable on most doors, which is far cheaper than a new curtain.

Guide wear. The curtain rides in steel guides on each side, and years of cycling wears the wear-strips inside them. A door that binds partway or drifts to one side is usually guides rather than the motor.

Barrel and spring tension. The counterbalance spring lives inside the barrel above the opening. When it loses tension the operator works against the full curtain weight and burns out — the same failure mode as a residential broken spring, on a much larger scale.

Bottom bar and astragal. The rubber seal on the bottom bar takes the impact of every close cycle and every strike. Cheap to replace, and it protects the slats above it.

A rolling steel door on a busy dock can cycle 40 times a day. That is 14,600 cycles a year, so a spring rated for 10,000 is exhausted in roughly eight months.

High-cycle barrel springs rated 50,000 to 100,000 cycles cost more up front and are standard on commercial doors for exactly this reason. Specifying a residential-grade spring on a commercial door is the most common way facilities end up with a door down twice a year.

A rolling steel door is usually the only way in or out of a bay. When it is stuck closed, that bay stops receiving; stuck open, the building is not secure and conditioned air is gone.

That is why commercial work is quoted on response time as much as on parts, and why a maintenance contract at $180 to $450 per visit is cheaper than one unplanned outage plus emergency labour.