927. The Wall Between Courtyards

Eiruvin 3:3

If there is a wall or a haystack lower than ten handbreadths in height (about 30”) in between two courtyards, they may only make a single eiruv and not two eiruvs; if ten handbreadths or taller, they must make two separate eiruvs. If there is a ladder on each side of the wall, it is considered an entrance and the residents may make a single eiruv if they desire. Even if the ladder is flush against the wall so that it cannot be used without moving the lower part away from the wall, it nevertheless enables them to make a single eiruv. Not only that, they may make a single eiruv even if the top of the ladder doesn’t reach the top of the wall so long as the gap is less than three handbreadths (about 9”).

Eiruvin 3:4

If the wall between courtyards is four handbreadths thick (about a foot) and there is a ladder on each side, the residents may make a single eiruv if they so desire. If the wall is not four handbreadths thick and there are fewer than three handbreadths (about 9”) between the ladders, they may make a single eiruv. If there are more than three handbreadths between the ladders, the residents may only make two separate eiruvs.