945. Landlords and Tenants

Eiruvin 4:14

If the owner of a courtyard rents houses to others with the condition that he can leave possessions or merchandise in each of these residences, the tenants do not impede the ability to carry. Since he retains his rights in each of the residences, the others are considered his guests. This is only when the things he has left in the houses may not be handled on Shabbos, like untithed produce or unprocessed metal. If he has left things that may be handled on Shabbos, the tenants do impede the ability to carry unless they make an eiruv. This is because the possibility exists that the landlord might remove his property on Shabbos, which would remove his stake in these residences.

Eiruvin 4:15

Let’s say that the residents of a courtyard forgot to make an eiruv. In such a case, they may not transfer objects between their houses and the courtyard or vice versa. When it comes to things that were left in the courtyard when Shabbos began, however, such things may be moved throughout the courtyard and its adjacent domains (roofs, etc. – see halacha 3:19). Let’s say that a porch or a loft opens to a courtyard, and that the residents of the courtyard and those of the porch have each made an eiruv for themselves. In such a case, when it comes to objects that were left in the houses when Shabbos  began, the residents of the porch or loft may carry them throughout the porch or the loft and all of its adjacent domains. The residents of the courtyard may carry throughout the courtyard and its adjacent domains. Similarly, if one person lives in the courtyard and another lives in the loft, and they neglected to make an eiruv, the owner of the loft may carry throughout the loft and its adjacent domains, and the owner of the courtyard may carry throughout the courtyard and its adjacent domains.