Lomita is largely low-density detached housing built across the middle decades of the twentieth century, so a typical door was installed around the same time as the house. That is a long time for a door to be standing a couple of miles from the ocean, and it explains most of what we find.
What your door probably is
Doors installed in the 1940s to 1960s are, in broad terms, one of three things.
- Extension-spring steel. Springs running along the ceiling to either side, with cables down to the bottom corners. The most common configuration on doors of this age, and the highest-consequence one.
- Early torsion steel. Springs on a shaft above the door. Better, but at this age the springs are likely at the end of their life and the paint on them is likely breached.
- Wood or wood-composite. A face panel over a frame, sometimes with glass lites. Beautiful, sensitive to damp, and at this age frequently delaminating or swollen at the bottom edge.
Two minutes looking up from inside the garage will tell you which of the three you have.
What the heat does, and in what order
Lomita sits a couple of miles from the Pacific, and that combination — strong sun on the south and west faces, salt-laden air, and a modest temperature swing between day and night — does a specific kind of damage. Uninsulated panels take up heat through the afternoon and expand, and on a door of this age the deterioration appears in a fairly consistent order.
- Bottom seals and weatherstripping. The bottom of the door takes the worst of it: heat from the driveway, standing water in winter, and hard sun on the paint. It hardens, cracks and stops sealing first, and it is the cheapest thing on the list to replace.
- Paint failure on the sun-facing panels. On a single-layer steel door the exterior skin runs much hotter than the air. Paint chalks and fails, bare steel is exposed, and rust starts there rather than anywhere else.
- Bottom brackets and hinges. These carry more load on an old extension-spring door and work harder every cycle. A bottom bracket that has been flexing for decades develops play at the pin, which is what lets the roller leave the track.
- Rollers and tracks. Expanded panels press harder on the rollers, so both wear faster. On original hardware this is the most common reason a door starts binding partway through travel.
- Cable drums. A grooved or seized drum cuts a new cable at the same point every cycle, which is why cables sometimes fail soon after being replaced. A seized drum puts a permanent twist into the cable.
- Springs. The paint coating that protects a spring is easily breached by handling, and rust then thins the metal invisibly underneath. The paint marks on the cone tell you how much travel is left.
- Wood doors. Swelling and delamination start at the bottom edge, which is the part that stays damp longest after it rains.
None of this is preventable indefinitely. It can be caught early, which is what makes a regular check worth doing on a door of this age.
What is worth doing on an older door
- Convert extension springs to torsion. The single most valuable safety improvement available on an older door. It moves the highest-energy component from the middle of the garage to the top, where it is contained. Usually worth doing while we are already replacing the cables.
- Replace bottom brackets and hardware before they corrode through, not after.
- Replace the bottom seal and weatherstripping. Cheap, and on a door this age it makes a real difference to drafts, noise, and whether the door closes cleanly.
- Have the door re-balanced if it has been repaired over the years, especially if the springs were ever changed.
- Check the paint marks on the torsion springs, and treat closed or overlapping marks as a reason to call.
- Consider a new insulated door if the garage is attached, heated, or used as a room. A single-skin steel door is the biggest heat loss in a heated garage.
And one that is worth saying plainly: an older door in good condition is not automatically a door to replace. Many of these are worth another decade with cables and a tune-up.
What not to do on an older door
- Do not attempt the springs. On an older door with extension springs in particular, this is where serious injuries happen.
- Do not paint over a rust bloom on a spring. It hides the only warning you get.
- Do not fit a cheap or incorrectly sized spring. This is the single most common reason a door becomes permanently heavy, and it happens because someone replaced a spring badly once.
- Do not leave an old bottom bracket until it fails. When it lets go, the door comes off its rollers and the roller and cable damage that follows is a bigger job.
- Do not ignore a cable that has been replaced recently and is fraying again. Repeated cable failure points at a grooved drum, not at the cables.
- Do not assume a door is fine because it opens. A door that opens with a snapped cable and a bent bottom bracket is a door one bad day away from coming down.