Durability begins with refusal: rain beads on a worn stone lintel, then slips away before roots can widen a seam. Heat is not the executioner. Where builders chose dense volcanic rock or quartz-rich sandstone, low connected porosity slows capillary uptake, while thick blocks spread stress long after wooden roofs have failed.
The popular explanation, that old stone merely outlasts everything, misses the disciplined engineering in plain sight. Mass still matters. Deep foundations and gravity-loaded joints keep compressive forces aligned, so a gate can settle without turning each small movement into a fracture. Mortar takes the punishment. Its greater permeability can release moisture and salts before crystallization pressure attacks the block itself; badly matched hard cement reverses that bargain. Shade helps, oddly. Eaves, recesses, and projecting caps limit wet-dry cycling, the repeated expansion and contraction that turns a hairline crack into a route for roots.
Plants are less invincible than photographs suggest. The image lies. A rooted fig can split masonry, yet vines usually flourish where joints were already open and drainage had already failed. Survival is selective, not magical: standing gates tend to have repairable joints, runoff routes, and mineral grains that resist dissolution. Rain keeps the final account.
