942. Non-Residence Structures in a Courtyard

Eiruvin 4:8

If a person owns a gatehouse through which people often walk, a portico, a porch, a barn, a shed for straw or wood, or a storehouse in a courtyard belonging to someone else, he does not impede that person’s right to carry in the courtyard. An eiruv is only necessary to enable carrying when one possesses a dwelling place in a courtyard where he eats a meal. A place to sleep does not impede the ability to carry. This is why, even if a one regularly eats his meals in a gatehouse or a portico, he does not impede carrying, since it is not considered a dwelling.

Eiruvin 4:9

Let’s say that there are ten residences, each inside the next. The occupants of the innermost residence and the one around it must provide the eiruv, while the eight outermost residences need not contribute. This is because many people walk through the outermost residences, making them the functional equivalent of a gatehouse. As noted, one who lives in a gatehouse does not impede others’ ability to carry. The ninth (i.e., the next-to-innermost) residence does not have so many people passing through it, just the occupants of the innermost residence. This does impede their ability to carry, necessitating that an eiruv be made between these two dwellings.