Locks and doors · 15 September 2026 · 5 min read
Why Locks Stiffen by the Sea in Alicante, and What Helps
Why keys start to catch in flats near the Postiguet, Albufereta and San Juan, what actually helps, and when the cylinder is finished.
If you live near the sea in Alicante, you have probably felt it: a key that used to glide now needs a wiggle, a quarter-turn back, a little push. It rarely happens overnight, and it rarely fixes itself.
What is happening inside the lock
A standard cylinder is a brass housing with rows of small spring-loaded pins. Your key lifts each pin to exactly the right height so the plug can turn. When the pins, springs or the plug surface corrode even slightly, the tolerances that let the key turn smoothly are lost.
Alicante gives that process plenty of help. AEMET’s standard climate values for the city put the average relative humidity at 66 per cent, and the flats that face the water along the Postiguet, Albufereta, Playa de San Juan and Urbanova take salt on the breeze as well. Brass resists better than steel, but the springs inside do not.
What helps
- Dry lubricant. Graphite powder or a PTFE dry spray, a short burst into the keyway, then work the key in and out several times.
- Clean keys. A key that lives in a beach bag carries sand into the lock every time it goes in.
- Use the lock. A door that is locked and unlocked every day stays freer than one that is left for weeks.
What makes it worse
- Cooking oil, WD-40-style penetrating sprays and grease. They feel like an instant fix, then collect dust and grit and gum the pins solid.
- Forcing the key. Keys snap at the shoulder, and a stub left inside a stiff cylinder is a longer job.
- A copy of a copy. Worn keys ask more of an already tired lock.
When it is time to change the cylinder
If you have lubricated it properly and it still catches, or it only works when the door is pushed or pulled, the cylinder is near the end. It is a quick, cheap part to swap on a planned visit, and far less trouble than the night it finally refuses to turn with you on the wrong side.
It is also a good moment to upgrade. Many doors still carry basic cylinders; an anti-bump, anti-snap one fits the same hole.
A note for owners who are away
About one home in five in Playa de San Juan is classed as empty in the city’s housing study. A seafront lock left unturned for months is the one most likely to seize. If that is your flat, read what to check when you come back.