1,304. A Building with a Body in It

202:2 A kohein is not allowed to enter a building that has a dead person inside it. This is true even if it's very large, and even if the deceased and the kohein are in separate rooms if the wall separating them has an opening of a handbreadth by a handbreadth. This is because an opening of a handbreadth by a handbreadth transmits the ritual impurity between rooms. (A handbreadth is about three and a half inches.)

Similarly, if the second room opens to a third room and between them there's another opening of a handbreadth by a handbreadth, then the ritual impurity continues to the third room. This could potentially continue ad infinitum. If an opening was made to admit light, it transmits ritual impurity even if it's the size of a small coin.

202:3 In cities such as ours, the roofs of houses project outward by the width of a handbreadth. It has been established that the width of a handbreadth transmits ritual impurity, in which case the overhanging roof is like a canopy and transmits the impurity.

Because of this, if there's a dead person in one of two houses that are next to each other, the impurity can be transmitted via a door or a window under the edges of the projecting roofs and into the second house via a window or an open door. Therefore, a kohein is not permitted to enter the other house, either. This can be equally true for multiple houses that are next to each other in succession.