Aluminum cladding

As a teenager the editor worked on the family farm in New Zealand. They had a hay-barn of unlined timber construction. The outer cladding on the roof and walls was corrugated Aluminum sheeting nailed with aluminum alloy nails. The aluminum was light, bright and shiny, and did not need painting, but it was soft, corroded quickly where in contact with the ground, and the nails slowly worked loose. In the evening as the temperature dropped the aluminum cladding popped and banged for hours like gunshot. The neighbors iron-clad barn did the same thing but not as much.

Questions: 1 Account for the behavior of aluminum, compared iron cladding fixed with lead-head iron nails. 2 Why do small sheets of aluminium cladding not do the same thing on a roof in Bangkok? Next