(gathered by farmers clearing their fields) were a cheap and durable roofing material.

（由清理田地的农民收集）是一种廉价耐用的屋顶材料。

Steel rods provide a rigid structure, and roofs are covered by roofing material, but there is no need for bricks or concrete.

而钢条能提供坚固的结构，屋顶覆盖有屋面材料，但是无需砖头或混凝土。

A representative for the charity said that people whose homes had been submerged were living in boats and trying to protect their roofing material from looters.

该慈善机构的一名代表称，房屋被淹没的人正住在船上，并试图保护他们的屋顶材料不被抢劫者抢走。