What a steel shop building changes about its overhead door

Drive any county road between Ponca City and Newkirk and the shop buildings are easy to pick out. Ribbed steel walls and one or two big doors on the gable end or the eave side. Some hold a pickup and a mower. Some hold equipment that needs every inch of the opening.

On a house, the garage door sits in a wall that is framed and sheathed all the way around it. On a steel building, the walls are thin metal skin screwed to horizontal girts that run between columns. None of that can hold a door, so the door gets an opening framed for it.

What does an overhead door hang on in a metal shop building?

It hangs on the framed opening: two jambs and a header that tie into the building’s steel frame, either steel channel or wood bolted to the steel. The track brackets lag or bolt into those jambs, and the spring anchor lands on the header. Nothing structural goes into the ribbed skin. Most commercial garage door repair on a shop starts with a look at that frame.

On some buildings the door hardware bolts straight to steel jambs that came with the building. On a lot of others, wood is fastened to the inside face of the steel and the brackets lag into that wood. Both work, but a jamb board that has taken rain at the bottom for years is a weaker anchor than it was when the building went up.

The header matters too. A torsion spring pulls against its anchor plate every time the door moves, and when the header is a light piece that was there mostly to close the gap above the door, that pull can twist it over time.

Wind on a wide door loads the same jambs sideways, which the wind load and bracing guide covers.

Why does a shop door bind or gap when the house door never did?

The door follows the frame. If the opening is out of square or the slab at the door line is not level, the door shows it. It rubs at one spot in its travel, or it closes with a gap at one bottom corner. A house wall around a garage opening is stiff and rarely moves. On a steel building, the opening is the soft spot.

What pushes a shop opening out of line:

• Jambs set a hair out of plumb when the building went up.
• A jamb or girt that took a hit from a bucket or a trailer tongue and got pushed back by eye.
• Steel that grows and shrinks between a July afternoon and a January night, carrying the jambs with it.
• A slab that slopes toward the door for drainage, so one side of the bottom section meets concrete first.

New panels do not fix any of that. The track has to be set to the opening as it actually stands, not as a tape measure says it should be.

One check you can make with the door closed. Measure across between the two vertical tracks at knee height, then again at head height. If the numbers differ, the tracks are not parallel and the door is being pinched or let loose somewhere in its travel.

What track does a tall shop door need?

That depends on the room above the door. The space between the top of the opening and the lowest thing overhead, whether that is the eave, a truss or a light, decides between standard, high-lift and vertical-lift track. Standard track turns the door flat right above the header. High-lift runs it further up the wall before it turns. Vertical-lift takes it straight up and never turns it.

High-lift is the usual answer in a shop with tall side walls. The door climbs most of the way up the wall before it turns, so the horizontal run sits high in the building and stays out of the way of whatever is parked under it. Vertical lift fits a building whose walls run well above the opening, with the door stacked straight up the inside of the wall.

Shops collect things overhead, though. A hanging heater or a vehicle lift raised over a pickup can sit right where a horizontal track wants to run. The track choice gets made from a look up at the ceiling with everything in front of the door in view.

What changes on the springs and cable drums when the door is 12 or 14 feet tall?

A taller door is a heavier door, and on high-lift track it also climbs the wall with its full weight on the cables before it turns. High-lift drums have a tapered section that takes up cable during that climb and a straight section for the turn. The springs are sized for the weight and wound for the longer travel, and they have to match those drums.

Put standard drums on high-lift track, or a spring wound for a standard lift, and the door can feel fine near the floor and wrong near the top. It drifts down from fully open or will not hold where you stop it.

The weight gets measured on the real door before a spring is chosen, which is the same rule our garage door spring repair page lays out for residential doors. A shop door often carries a pair of springs or more on one shaft across a wider header, and a longer cable run puts more cable down at the bottom corners where grit and water sit. A frayed strand on a door this heavy is worth a call before it lets go.

Why does a high-lift track change where the opener goes?

A trolley opener hangs from the ceiling and pulls the door along a rail through the turn. On high-lift track the door turns well above the header, so there is no room for a ceiling rail to meet it. A wall-mounted jackshaft opener sits beside the door and turns the torsion shaft directly, so it does not care how high the door turns.

That is why so many tall shop doors end up with a jackshaft unit at one end of the spring shaft. Nothing hangs from the ceiling in front of the door, which matters in a shop with a lift or a hoist near the front, and on a vertical-lift door it is close to the only practical way to motorize the door at all.

An opener that strains on a heavy shop door is often telling you about the springs rather than the motor. A garage door opener repair visit checks the door’s balance before anything else.

Where do dirt, water and mice get in around a shop door on a metal wall?

At the head of the opening, where the ribbed wall panels are cut across their ribs, and at the bottom, where a straight seal meets a slab that is not straight. Cut ribs leave a row of small open channels above the door unless something fills them, and an uneven slab leaves a gap under part of the bottom seal.

Foam closure strips shaped to the rib profile fill those channels, and on older shops they are often missing or chewed. Down the jambs the gap is between the door face and the trim, which jamb seals close. Those seals are standard parts on any commercial overhead door, and when they are gone, wind pushes dust through and mice walk in.

At the bottom, the seal has to cover a slab edge that is often sloped, or chipped where tires cross it. A thin seal that touches concrete at one corner and hangs in the air at the other is the most common gap on a shop door. A taller bottom seal that takes up the low side closes it.

Red dirt finds the same openings on a shop that it finds on a house, and what it does to rollers once inside is on the tune-up guide. To find the gaps themselves, stand inside on a bright afternoon with the shop lights off and look for daylight along the jambs, across the head and under the bottom seal.