Squatting is the action of occupying an abandoned or unoccupied area of land or a building, usually residential, that the squatter does not own, rent or otherwise have lawful permission to use. United Nations estimated in 2003 there were one billion slum residents and squatters globally. Squatting occurs worldwide and tends to occur when people who are poor and homeless find empty buildings or land to occupy for housing.

A house is a single-unit residential building, which may range in complexity from a rudimentary hut to a complex structure of wood, masonry, concrete or other material, outfitted with plumbing, electrical, and heating, ventilation, and air conditioning systems. Houses use a range of different roofing systems to keep precipitation such as rain from getting into the dwelling space. Houses may have doors or locks to secure the dwelling space and protect its inhabitants and contents from burglars or other trespassers.