History of garage doors Part Three

Steel stamped construction

A common material for a new garage door is steel sheet formed or stamped to look like a raised panel wooden door. Steel doors are available in uninsulated, insulated, and double skin steel. A design mimicking carriage house doors has become popular since early 2000s, and many manufacturers clad the exterior of a steel door with composite, vinyl boards, or other trim to give it the appearance of wood.

Insulation

In situations involving residential attached garages where the insulating value and the energy efficiency of a garage door is important to prevent overheating and freezing problems, as well as for comfort and energy savings.

Some manufacturers advertise very high insulating values for some of their garage doors (R-15 to R-17), but it may be true for only for some central sections. The actual R-values – for the entire door – are often 1/2 or 1/3 of the advertised value.

Torsion spring lift mechanism

A torsion spring counterbalance system consists of one or two tightly wound up springs on a steel shaft with cable drums at both ends. The entire apparatus mounts on the header wall above the garage door and has three supports: a center bearing plate with a steel or nylon bearing and two end bearing plates at both ends. The springs themselves consist of the steel wire with a stationary cone at one end and a winding cone at the other end. The stationary cone is attached to the center bearing plate. The winding cone consists of holes every 90 degrees for winding the springs and two set screws to secure the springs to the shaft. Steel counterbalance cables run from the roller brackets at the bottom corners of the door to a notch in the cable drums. When the door is raised, the springs unwind and the stored tension lifts the door by turning the shaft, thus turning the cable drums, wrapping the cables around the grooves on the cable drums. When the door is lowered, the cables unwrap from the drums and the springs are rewound to full tension.

Life of torsion spring

Garage door manufacturers typically produce garage doors fitted with torsion springs that provide a minimum of 10,000 to 15,000 cycles and are guaranteed for three to seven years. One cycle is a single opening and closing sequence. Most manufacturers offer a 30,000 cycle spring. However, it is important to remember that if the weight of the garage door is increased by adding glass, additional insulation, or even several coats of paint, the life of the torsion spring may be greatly reduced. Additionally, springs at highly humid environments, such as coastal regions tend to have a significantly shorter cycle life, due to the corrosive cracking.

Other factors like poor garage door maintenance, loose tracks, or components shorten torsion spring life. Owners are advised to avoid applying grease to garage door tracks because that makes the wheels "skate" in the track instead of turning on their bearings. Only bearings, hinges, and spring wire require lubricant.

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