Humidity, salt and how long a garage door lasts by the water

Two identical doors, installed the same week, one at Belmont and one at Wangi. Ten years on, the Belmont door has been through a spring, runs rust freckles down its tracks and wants its third seal; the Wangi door is just getting interesting. Nothing was wrong with the Belmont install. It just lives on the other clock.

What the air is doing

Salt is the famous one: it rides sea spray and humid onshore air, settles on steel, and holds moisture against it, which is corrosion's whole recipe. The channel end of the lake, where ocean and lake trade water twice a day, has the saltiest air on our chart, and the southerly delivers it up the eastern shore as far as the Belmont flats. Humidity is the quiet accomplice everywhere else: this is a genuinely damp coastal district, wettest through winter, and lakeside mornings keep hardware wet for hours at a time even where salt is thin.

Where it shows first, in order

• Springs. A torsion spring is high-tension steel doing thousands of flex cycles; surface rust pits it and pits become failure points. Salt-side springs routinely retire before their cycle count says they should.
• Lift cables. Stranded wire holds moisture in its lay. Fraying at the bottom fitting is the tell, and a frayed cable is an urgent booking, not a watch-item.
• Track edges and fixings. Cut steel edges and screw heads rust first because that's where coatings are thinnest. Cosmetic at first, structural eventually.
• Bottom rails and seals. The lowest steel lives in splash and leaf-litter damp. On lakeside streets this is the first thing we photograph for a condition note.
• The door face, last. Modern coated steel faces resist salt well; by the time a face is blistering, the working parts underneath are usually long overdue.

The clocks, roughly

We won't invent precise lifespans, too much depends on the individual door and its maintenance, but the working shape is this: channel-side hardware runs on the fastest clock on the lake; sheltered east-shore and lakeside suburbs run a middle clock where humidity, not salt, does the ageing; the western shore and the ridge run the slow clock, where age and use decide things and salt is barely a factor. The practical differences: on the fast clock, yearly servicing and galvanised or stainless replacement hardware pay for themselves; on the middle clock, seals and lubrication carry the load; on the slow clock, an honest service every couple of years keeps faith with a door that's mostly minding its own business.

What actually helps, channel-side

• Fresh water, occasionally. A soft hose-down of tracks and the door's lower edge after a big blow rinses the salt load off. Cheap and genuinely effective; keep water away from the opener.
• Lubrication on schedule, because lubricant film is also a moisture barrier on springs and hinges.
• Spec for the postcode at replacement time. Galvanised tracks, stainless fixings and coated springs cost a little more once and pay it back for years. It's our default spec on Sheet 1, argued at every quote.

If you want your own door placed on the clock, that's what the Run Sheet does in thirty seconds, or a service visit does it with hands on the steel.