82:7 If a courtyard or house opens into a street and its door opens inward, and the door posts and the lintel above them and the step below them are on the side facing the street, then this area is sometimes considered a private domain and sometimes considered a carmelis (the quasi-public domain). Since not everyone is expert in this field, we apply to it both the stringencies of a private domain and those of a carmelis. It is therefore prohibited to take from this area to the street, which is a public domain, or to a carmelis. Likewise, one must not bring something in from the street because it could be considered a private domain. Nor may one bring something there from the house or the courtyard or vice versa, because it could be a carmelis. Therefore, if the door is locked and one needs to open it, he must have a non-Jew insert the key into the lock and, after unlocking it, remove the key before the Jew opens the door. This is because if the Jew opens the door with the key still in the lock, he would be moving the key from a carmelis into a private domain.
82:8 In many places, there are houses where the roof extends from the wall of the house into the street, where it is supported by pillars. In such a case, one may not bring something there from the house or vice versa. Similarly, one may not carry an object four cubits there because it is considered a public domain or a carmelis, just like the street. Even though the roof is on pillars, which gives it the shape of a doorway and it is considered a partition, in any event there are no partitions on the sides to make it a private domain. To rectify this, one must erect a pole by the wall that has the roof on it so that there will also be the shape of a doorway on that side; one must do likewise at the other end. If several adjacent houses all have the same type of roof, it is sufficient for them to do this with the houses that are at either end, and then to combine all the houses in the courtyard through eiruvei chatzeiros. (The laws of eiruvei chatzeiros are discussed in chapter 94.)