Why a 16-foot Dunwoody garage door bows in the middle
Open a two-car garage door and look at it from the end of the driveway. On a door in good shape, the bottom edge sits tucked up behind the header in one straight line. On a door with a bow in it, a shallow curve of it shows below the header in the middle while both ends stay out of sight.
Why is the open garage door drooping over the car?
Open, a two-car door is a 16-foot panel lying flat under the ceiling, held only at its two edges by the rollers in the horizontal tracks. Nothing holds up the middle except the door’s own stiffness and whatever steel struts are fastened across its sections. When that stiffness goes, the middle sags. A dip you can see from the driveway is a job for garage door repair in Dunwoody before the bend reaches the hardware.
Some give is normal on a door that wide. Sixteen feet of steel or wood flexes as it rolls through the curve at the top of the tracks. What is not normal is a dip that stays once the door has stopped, or one that is deeper this fall than it was last spring.
The opener adds a second load. Its arm is bolted to the center of the top section and pulls on that one spot every cycle, hardest when it starts the door up out of the opening. A stiff section spreads that pull across its width. A soft one bends at the bracket, a little further each time.
Which Dunwoody doors bow, and which hold their line?
Dunwoody’s bowing doubles are mostly of two kinds. The original wood doubles on the 1965 to 1975 split-levels in Kingsley and Mill Glen are heavy, and the joints between their rails and stiles work loose after fifty summers of swelling in the humidity and drying out again. Each section gets a little less rigid, and the door sags as a whole.
The other is the first-generation steel double that went onto the 1976 to 1988 two-stories in Wynterhall and Redfield as a 1990s replacement: one thin skin of steel per section, with one strut at most, usually on the top section for the opener. A newer insulated steel door holds a straighter line, since the foam core inside each section stiffens it from face to face.
What does a bowed door do to the rest of the door?
The bend works its way into the hardware, starting with the hinges along the middle of the door, where it flexes most. Nearly all of it can be read with the door at rest, either from the driveway with the door up or from the doorway into the garage with it closed. Nobody needs to stand under an open door to see any of this.
- Cracked hinges along the middle of the door, or a hinge line that no longer runs straight from section to section.
- The rollers at each end riding shallow in their tracks, drawn toward the center as the door bows. Pulled far enough, a roller leaves its track, and that is a garage door coming off its track.
- A crease or a kink in the top section where the opener’s arm bracket is fastened.
- A gap under the center of the closed door while both ends sit on the slab.
- An opener that strains louder than it used to, or a door that rubs along one side.
A door bowed far enough to pull its rollers out of line is not run again until a pro has looked at it. Stop using it where it sits, pull the opener’s plug, and park in the driveway for now.
What straightens a bowed door: struts, hinges, or springs?
Steel struts do most of the work. A reinforcing strut is a length of formed steel fastened across a section from end to end, and on a bowed section it brings the door back to a straight line and holds it there. The top section usually gets one along with a reinforcement bracket where the opener’s arm meets it, so the pull lands on steel instead of the door’s skin. Cracked hinges are replaced at the same visit.
How many sections need a strut depends on how far the bow has spread, and on a wood double it can be every one of them.
Then the springs. Struts add weight the springs were not set for, so the door is rebalanced at the same visit and re-sprung if the added weight calls for it. Spring tension is set for one weight of door, and winding it to a new one is the pro’s part of the job. On a 16-foot double that means torsion springs sized to the door as it now stands. The opener’s force setting is checked last, against the straightened door.
When is a bowed door the reason to replace it?
When the door itself is breaking down, not only flexing. A wood double whose joints have loosened bows and racks between its rails, and steel fastened to wood that is coming apart does not hold it straight for long. A steel double with a creased top section and cracked hinges across several sections has been bending for years. A door that bows back after struts went on is past what struts can fix.
Any of those is a door the pro will quote both ways. The math on that choice is on the page about whether to repair or replace a Dunwoody garage door. A new 16 by 7 insulated steel door runs $1,900 to $4,200 installed, and the price page puts what a new double door costs here next to the repair figures.
A bowed door is quoted at the house, since how far the bend has gone into each section is something the pro reads in person. The visit is $79 to $129, applied to the repair when you go ahead.
When it is time to call: garage door repair in Dunwoody, down to the door's own straight line.