Tarpaulins are used in many ways to protect persons and things from wind, rain, and sunlight. They are used during construction or after disasters to protect partially built or damaged structures, to prevent mess during painting and similar activities, and to contain and collect debris. They are used to protect the loads of open trucks and wagons, to keep wood piles dry, and for shelters such as tents or other temporary structures. Tarpaulins are also used for advertisement printing, most notably for billboards. Perforated tarpaulins are typically used for medium to large advertising, or for protection on scaffoldings, the aim of the perforations (from 20% to 70%) is to reduce wind vulnerability.