The author shows that the context of population growth and limited access to illegal land in Santiago lead to an increasingly explosive process of “allegamiento” (housing sharing). It is explosive because of the number of families involved in such survival conditions, as well as for the fact that most of them would prefer substandard solutions if their privacy is increased. The article shows further who this allegados are in Santiago in three different perspectives: from a survey performed in 1985, from the difference between household estimates and housing stock, and from the difference in the counting of nuclear families and the number of houses. The conclusion is that conditions are so poor in such housing alternative, that it can not be viewed other than as a transient solution, and as such, highly unstable.