(YD 362:1, 4)
Is it permissible to bury one person above another?
Is it permissible to bury a person in a mausoleum?
1) The halakhah permits the burial of one person above another. This was the decision of Rav Hai Gaon, which was accepted by all subsequent authorities. However, as the Shulhan Arukh states, one should leave a space of six tefahim (48 or 57.6 cm) of earth between the two graves.
Yet even though this was a common custom in Europe, certain families may view it as a lack of respect to the deceased. For this reason, in order to avoid tension, one should only do this with the agreement of both families, and it is preferable to perform this kind of burial with members of the same family.
2) It is not permitted to bury a person in a mausoleum constructed above the ground. It is true that in the Biblical and Rabbinic periods, people were buried in burial caves which resemble mausolea, but those caves were beneath the ground while mausolea are above the ground. Rabbis who permit burial in mausolea point to a few archaeological precedents, but those examples are extremely rare and represent the exception to the rule. They also point to two passages in the Talmud, which seem to speak about burial in buildings above the ground, yet those passages are far from clear.
On the other hand, it is a rabbinic commandment to bury Jews in the ground (Sanhedrin 46b); a mausoleum does not allow contact with the earth and is therefore forbidden.
Finally, there is an emotional side to this question. The average Jew will have difficulty viewing a mausoleum as a Jewish cemetery. The Jewish people throughout the generations has buried its dead in burial caves or in the ground and no lenient ruling can erase this historical memory.
Rabbi David Golinkin