Question: Should one affix a mezuzah on both sides of the doorpost when there is a doubt which is the proper side for the mezuzah?
Short Answer: Although some poskim suggest this idea, most poskim hold that this should not be done because it is a problem of Bal Tosif (adding on to the mitzvah) or michzei k’Bal Tosif (looks like you are adding on to the mitzvah).
Explanation:
I. The Problem
There is a multi-prong analysis that must be performed when determining which side of the doorway gets the mezuzah. See K’vius Mezuzah K’Hilchasah (Chap. 10). Seemingly, it would be much simpler (albeit, much more expensive!) to just affix a mezuzah on both sides of the doorpost any time there is a machlokes. Indeed, this would appear to be halachically preferable, as you satisfy all opinions.
However, the poskim dispute whether this is a good or a bad idea.
II. The Yaavetz
The Yaavetz (Sh’eilas Yaavetz 70), in the early 1700s, discusses a case where the side of the mezuzah is unclear, i.e., a backyard area. The door to the room swung open into both rooms (one of the prongs to determine the side for the mezuzah). The Yaavetz ruled that you should affix a mezuzah on both sides of the doorway, but without a brachah (in that situation). Clearly, the Yaavetz had no problem, and in fact, thought it preferable, to affix two mezuzos in cases of doubt.
III. Maharam Shick vs. Binyan Tzion
Approximately one century later, the Maharam Shick and the Binyan Tzion disputed this very issue in a series of letters to each other. The Maharam Shick (Yoreh Dei’ah 287) reviewed a t’shuvah by the Binyan Tzion who discussed whether a large room entering into a small room needs a mezuzah, and on which side should it be affixed. The Maharam Shick, towards the end of the t’shuvah, writes that you should certainly not place a mezuzah on both sides, as this is Bal Tosif (“BT”).
Even though BT is generally only violated when you intend to add on to a mitzvah, the Maharam Shick clarifies that here, since it is still during the “z’man mitzvah,” no intent is necessary to violate BT. Indeed, the Gemara (Rosh HaShanah 28b) is clear that one may not put a mixture of “one-corner” and “four-corner” blood on all four corners of the Mizbei’ach, as it is BT for the “one-corner” blood. Since it is z’man mitzvah, intent is irrelevant. The Maharam Shick adds that wearing t’filin of Rashi and Rabbeinu Tam is not problematic, as each t’filin is not a kosher pair according to the other opinion, so it is not BT.
This is in contrast to mezuzah, which would be BT if you placed on both sides, as each mezuzah is itself fundamentally kosher; it just might be in the wrong location. This is similar to tzitzis, where five strings on five corners is expressly BT, even though the fifth set of strings is placed in the wrong place. Therefore, one should not place two kosher mezuzos on a doorway in a case of doubt. See also Daas K’doshim (Yoreh Dei’ah 289:8).
The Binyan Tzion (100) disagrees. After citing the Maharam Shick and his concern for BT, the Binyan Tzion responded that the comparison to tzitzis is imprecise. By tzitzis, if you remove any one of the sets of strings, you have a kosher, four-set pair of tzitzis. Thus, the extra set is BT. In contrast, if you remove one of the mezuzos, you might not have fulfilled mezuzah on this doorway (as the other side might be the incorrect side). This is more akin to t’filin, that according to Rabbeinu Tam, Rashi’s t’filin are in the wrong order of parshiyos. Thus, wearing both, or affixing mezuzos on both sides of the doorway, is not BT. [Affixing two mezuzos on one side of the doorway would be BT, though].
The Binyan Tzion concludes by citing the Yaavetz (above) who previously held that mezuzos on both sides is permissible (without addressing BT).
IV. Practical Halachah
The Minchas Elazar (2:40) discusses the above sources. He notes that there is no issue of BT, as it is merely a safeik which is the right side. In theory, a safeik case would require a mezuzah on both sides, especially in a situation where there is a machlokes which side it should be placed (as opposed to a case where the “usage” of the rooms is equal). However, he concludes that he has never seen any g’dolim affix two mezuzos, so it is preferable to rely upon one opinion and just affix one mezuzah.
The K’vius Mezuzah K’Hilchasah (13:14) likewise concludes not to affix mezuzos on each side of the doorway. He cites the lenient opinions, as well, but notes that regardless, there should be a problem of “mechzi” like BT, similar to the idea we find by lulav. The Magid Mishneh (Hilchos Lulav 7:6) writes that you should not bind a non-arbaah minim species together with the arbaah minim – even though it is not actually BT – because it “appears” to be BT.
Similarly, the Igros Moshe (Yoreh Dei’ah 1:176) seemingly rejects the idea of mezuzos on both doorways, and expressly disagrees with the Yaavetz.
Rabbi Daniel Mann shlita sums this topic up nicely, when he writes that “[a]mong contemporary poskim, while there is no clear consensus,” but that “the stronger opinion is to not sanction mezuzos on opposite door posts, whether as a clear ruling (Minchas Yitzchak 1:9) or as a practical preference (Sheivet HaLevi III:150; B’mar’eh HaBazak (IX:35). In addition to formalistic Bal Tosif issues, it is problematic policy to create an odd-looking new phenomenon of two mezuzos, even if it is out of a desire for stringency/covering all bases, which itself is very often a two-edged sword.” (See https://www.yeshiva.co/midrash/31290 .)
Rabbi Ephraim Glatt, Esq. is the Associate Rabbi at the Young Israel of Kew Gardens Hills, and he is a Partner at McGrail & Bensinger LLP, specializing in commercial litigation. Questions? Comments? Email This email address is being protected from spambots. You need JavaScript enabled to view it..
