Garage Door Panel and Section Replacement

How a sectional door is built

Most residential doors are made of four or five sections stacked on top of each other and joined by hinges. On a steel door, each section has a thin outer skin pressed with the panel design, steel end stiles on the sides and, on better doors, a back skin with insulation sandwiched in between. Skin thickness is described by gauge: the lower the number, the thicker the steel, and residential doors commonly use something in the mid-20s.

The hinges are numbered. The lowest hinges are usually number 1, and each section higher up uses a slightly taller hinge so the door leans gently against the stop molding when closed. When a section is replaced, the right hinges have to go back in the right places or the door will bind or gap.

When a section can be replaced

Sectional garage doors are built from four or five horizontal sections hinged together. In principle any one of them can be swapped. In practice, it depends on whether the manufacturer still makes that exact model, color, panel design and thickness.

• Door age. Doors from the last 10 to 15 years are the easiest to match. Older designs may be discontinued.
• Label. Most doors have a manufacturer sticker on the inside edge of a section or the end stile. A photo of it saves a lot of guesswork.
• Color fading. Even an exact replacement can look slightly different from panels that have faded in the sun for years. Some homeowners paint the whole door after the repair.
• Damage to the tracks or springs. If the impact also bent the tracks or racked the door, the repair grows.

The bottom section takes the most abuse

The bottom section sits in puddles, snowmelt and road salt and takes the hit when the door closes on something. On steel doors, rust often starts along the bottom edge where the weather seal retainer meets the skin. On wood doors, the bottom rail is usually the first part to rot.

Replacing the bottom section often includes a new bottom seal and retainer, which also fixes drafts and water coming in under the door. If several sections are damaged, compare the cost against a new door: the gap is often smaller than people expect.

Small dents and quick fixes

Not every dent needs a new section. Shallow dents in steel are cosmetic and do not affect how the door works. A dent that creases the section horizontally is different: it weakens the section and can make it bend when the door rolls up. A technician can add a reinforcing strut across a weakened section, which is common on wide double doors and doors with a heavy opener pulling on the top section.

What to have ready when you call

• A photo of the damaged section and the whole door from outside
• A photo of any manufacturer label on the inside of the door
• The door width and height, if you can measure it
• Whether the door still opens and closes normally

With that, the technician can often tell you on the phone whether a matching section is likely to be available.

What happens on the day

1. Release the spring tension

   For the bottom section, the springs are unwound first, because the lift cables attach to the bottom brackets.

2. Support the door

   The sections above are clamped or blocked so nothing moves while the damaged section is out.

3. Swap the section and hardware

   Hinges, rollers and brackets move to the new section, or are replaced if worn. The bottom seal and retainer are often renewed at the same time.

4. Rewind and balance

   The springs are wound back, and the door is balanced and checked for an even gap along the floor.

5. Test the opener

   Travel limits and auto-reverse are tested, since a new section can change the weight slightly.

Wood doors are a different job

Wood sectional doors are built from rails, stiles and inset panels, and a rotted bottom rail can sometimes be repaired by a carpenter or a door shop rather than replaced as a whole section. Matching an old wood door exactly is harder than matching steel, though, and a wood door that is rotting at the bottom is often letting water in along its other joints too.

If you love the look of wood but not the upkeep, composite and faux-wood steel doors are worth comparing. They take the abuse of puddles, salt and snow far better than real wood.

Car impacts and insurance

A section dented by a car is one of the most common reasons for this repair. Before anything is moved, take photos of the door from inside and outside, the tracks, and the vehicle. Many homeowners policies cover sudden accidental damage, subject to the deductible, and if someone else hit the door, their auto insurance may be responsible. Ask the technician for a written estimate that lists the damaged parts, since insurers usually want one.

Where calls are connected

Calls about panel & section replacement are taken across Long Island and upstate New York. On Long Island: Nassau County and Suffolk County. Upstate: Albany, Rensselaer, Saratoga, Schenectady, Warren, Washington, Columbia, Greene, Schoharie, Montgomery, Fulton, Otsego, Delaware counties.