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The Dimensions of the Sukka

  • Rav David Brofsky




The Chayye Adam (146:3) writes that it is a mitzva min ha-muvchar, halakhically preferable, to construct a sukka of four complete walls. The Talmud, however, records that a halakha le-Moshe mi-Sinai teaches that when constructed properly, two walls and an additional piece may suffice. 


            In this shiur, we will first discuss the general principles relating to the dimensions of a standard sukka of three or four complete walls, and then discuss how to construct a sukka consisting of fewer than three complete walls.


In order to understand the detailed laws regarding the dimensions of the sukka, we must first establish the equivalent contemporary measurements of the Talmud’s typical measurements – the tefach and amah.  The Acharonim disagree as to whether a tefach (handbreadth) is approximately 8 cm, the opinion of R. Chaim Na’eh, or approximately 10 cm, the opinion of the Chazon Ish. As a result, three tefachim, the measurement of “lavud” (to be defined), ranges between 24-30 cm; seven tefachim, the minimum length of the sukka’s walls, ranges between 56-70 cm; and ten tefachim, the minimum height of the sukka’s walls, is between 80-100 cm. While some insist that one should preferably adopt the larger measurement of the Chazon Ish for matters of biblical origin, others insist that the halakha is in accordance with R. Chaim Na’eh. We will also encounter the measurement of four amot (190 cm–232 cm), ten amot (470 cm–590 cm), and twenty amot (940 cm-120 cm). 


Understanding of some Talmudic concepts is also essential before we explore the laws of the sukka. The Talmud (Shabbat 97a, Sukka 6b) records that halakha le-Moshe mi-Sinai teaches that two sections separated by a gap of less than three tefachim are considered to be “lavud” – connected.  Therefore, as we shall see, if a wall is within three tefachim of the ground, the sekhakh, or the corner, we overlook the gap and view the wall as connected to the other area. 


Minimum Height


The Talmud teaches that the walls of the sukka must be at least ten tefachim high (Sukka 2a; Shulchan Arukh 633:8). Based on the law of lavud, the gemara (16b) also teaches that the walls may be suspended within three tefachim of the ground.  Thus, one may theoretically use walls slightly more than seven tefachim high and suspend them slightly less than three tefachim from the ground. In addition, the gemara relates that even a wall of slightly more than four tefachim may be used.


R. Chisda stated in the name of Abimi: “A mat slightly more than four tefachim [wide] is permitted as a sukka wall.” How does one place it? One suspends it in the middle, less than three [tefachim] from the ground and less than three from the top, and whatever [space] is less than three tefachim is treated as lavud.  But is not this obvious? One might have said that we apply the law of lavud once, but we do not apply lavud twice [to the same wall]; therefore, he informed us of this.  It was objected: A mat slightly more than seven [tefachim] is permitted as a sukka wall! With reference to what was this taught? With reference to a large sukka.


In other words, when constructing a tall sukka, one may use a wall of slightly more than seven tefachim suspended within three tefachim from the ground. When building a short sukka, ten tefachim high, one can even use a wall of slightly more than four tefachim, suspended within three tefachim of both the ground and the sekhakh, using the principle of lavud twice (Shulchan Arukh 630:9). 


Often, especially when sukkot are built using pre-existing walls (such as on a balcony), the walls of the sukka do not reach the sekhakh. The Talmud (Sukka 16a) teaches that the walls don’t have to reach the sekhakh, as long as they line up with the sekhakh (Sukka 16a).  Upon what is this leniency based?


On the one hand, one might base this upon the halakhic principle of gud asik mechitzata, which states that we consider a valid mechitza as if it projects upwards or downwards (see Ritva 16a). Interestingly, however, we find that the gemara (4b) cites a dispute regarding whether and the extent to which this principle should be applied to the laws of sukka.  The gemara, for example, relates that R. Yaakov maintains that one can place sekhakh on four poles positioned on the top of a building; the four walls of the building, projecting upwards, will serve as the walls of the sukka. R. Yaakov bases this upon the principle of gud asik mechitzata, but the Sages disagree. Furthermore, the gemara questions whether one must align the poles and the sekhakh with the outer walls of the building, or whether the poles and sekhakh may even be positioned in the middle of the roof. 


The Rambam (Hilkhot Sukka 4:11) rules in accordance with R. Yaakov; one may employ the principle of gud asik mechitzata, but only at the edge of the roof. The Rosh (1:6), however, rules that regardless of whether the poles are on the edge of the house or the center, the sukka is invalid. The Ran (2a s.v. ve-garsinan) explains that if we reject R. Yaakov completely, then we don’t find any application of gud asik mechitzata in the laws of sukka. The Shulchan Arukh (630:6) cites both opinions, and the Mishna Berura (30) rules stringently.


Some Acharonim (Penei Yehoshua 6b; Arukh La-Ner 6b; see also R. Tzvi Pesach Frank’s Mikra’ei Kodesh, Sukkot 1:7) note that according to the Ran, who seems to completely reject the application of gud asik mechitzata to the laws of sukka, one must find an alternate basis for allowing walls of ten tefachim that do not reach the sekhakh.  We might suggest that the four walls of the sukka do not, even theoretically, need to reach the sekhakh, as the gemara never intended that the four walls fully enclose the sukka, but merely demarcate the area of the sukka. As long one uses halakhically valid mechitzot, the sukka is valid.


The question of why we permit ten tefachim high walls that do not reach the sekhakh may have a practical ramification. The mishna (17a) teaches that as long as the walls are within three tefachim of the sekhakh, the sukka is valid. The Tur (630) and Shulchan Arukh (630:9) rule that even if the walls that are not directly under the sekhakh are only ten tefachim high, as long as they are within three tefachim inwards or outwards of the sekhakh, the sukka is valid. 


R. Akiva Eiger (Responsa 12) challenges this ruling. Assuming that one permits using walls of ten tefachim based upon the principle of gud asik mechitzata, he questions whether one may rely upon the leniencies of both lavud AND gud asik mechitzata simultaneously. The Ran (Sukka 9a) suggests that one may not rely upon both lavud and another leniency when validating a sukka.  Although R. Eiger and other Acharonim attempt to resolve this apparent contradiction, it is certainly true that if we allow walls of only ten tefachim because that is the base requirement of the walls of the sukka and not because we view them as projecting upwards (gud asik), his question does not concern us.


Maximum Height


Regarding the maximum height of the sukka, the mishna (Sukka 2a) records the following debate:


A sukka which is more than twenty cubits high is not valid. R. Yehuda, however, declares it valid.


The gemara offers three explanations of the first view.


Whence do we know this?

Rabba answered: Scripture says, “That your generations may know that I made the children of Israel to dwell in sukkot” – [with a sukka] up to twenty amot [high], a man knows that he is dwelling in a sukka, but with one higher than twenty amot, he does not know that he is dwelling in a sukka, since his eye does not see it.

R. Zeira replied: From the following verse, “And there shall be a booth for a shadow in the daytime from the heat” – [with a sukka] up to twenty amot [high], a man sits in the shade of the sukka; but with one higher than twenty amot, he sits not in the shade of the sukka, but in the shade of its walls…

Rava replied: [It is derived] from the following verse, “You shall dwell in booths seven days.” The Torah declared, For the whole seven days, leave your permanent abode and dwell in a temporary abode.  [With a sukka] up to twenty amot [high], a man makes his abode a temporary one; [in one] higher than twenty amot, a man does not make his abode temporary, but permanent.


The gemara explains that there are numerous halakhic differences between these views.  For example, what if the sukka is more than twenty amot high but the walls reach the sekhakh? According to Rabba, in this case one may still be conscience of the sekhakh, but according the R. Zeira and Rava, the sukka is still invalid. Alternatively, what if the sukka is higher than twenty amot, but the sukka is also wider than four amot? While according the R. Zeira, the sukka may be valid, as one sits in the shade of the sekhakh, according to Rabba and Rava, the sukka would still be invalid. 


Assuming that the halakha is in accordance with the view in the mishna and a sukka taller than twenty amot is invalid, which reason offered by the Amoraim is accepted? Although some (Rabbeinu Chananel, Ra’avad, the Ittur) accept the view of Rabba, the Rif and the Rambam (Hillkhot Sukka 4:1) rule in accordance with Rava: the sukka must be a temporary abode, and therefore regardless of whether the walls reach the sekhakh or the width of the sukka exceeds four amot, the sukka is invalid. 


The gemara (Sukka 4a) discusses numerous ways of validating a sukka whose walls are over twenty amot high. 


Minimum Area


The gemara (3a) records three opinions regarding the minimum area of a sukka.  Rebbe believes that the minimum area of a sukka is four amot by four amot.  Beit Hillel maintains that a sukka into which one can fit one’s head and most of one’s body, which the Rabbis estimate at about six tefachim by six tefachim, suffices.  Beit Shammai rules that the sukka must also be able to hold a small table, and therefore it must be at least seven tefachim by seven tefachim.  The gemara rules in accordance with Beit Shamai. 


The Acharonim discuss whether a sukka that is longer than seven tefachim but narrower than seven is valid. The Mishna Berura (634:1) writes that most Acharonim agree that this sukka is invalid. Furthermore, one may construct a sukka of other shapes, such as a circle, as long as a sukka of seven tefachim by seven tefachim can fit inside it (Shulchan Arukh 634:2). 


Constructing a Sukka from Two Walls


The Tosefta (1:6), cited in the gemara (Sukka 6b), brings a debate regarding the minimum amount of walls halakhically required for a sukka. 


Our Rabbis taught: Two [walls] must be of the prescribed dimensions (shenayim ke-hilkhatan), and the third [may be] even one tefach (handbreadth).  R. Shimon says: Three walls must be of the prescribed dimensions, and the fourth [may be] even one tefach (handbreadth). 


The gemara suggests different reasons for this debate and rules in accordance with the first view, which requires a minimum of two full walls and another partial wall. 


            Based upon what we learned above, a sukka consisting of three walls at least seven tefachim in length is valid.  According to the gemara, if one has only two full length walls, one may still construct a valid sukka using a partial wall. How and where must one construct the third, partial wall?


The gemara discusses two scenarios of “shenayim ke-hilkhatan.”  The first scenario (6b-7a) involves two walls placed at a right angle to each other:


Where is this tefach [of a wall] placed? Rav said: It is placed at a right angle to one of the projecting [walls]… It was also stated: Shmuel said in the name of Levi: It is placed at right angles to one of the projecting [walls], and so it is ruled in the Beit Ha-Midrash that it is placed at a right angle to one of the projecting [walls].  R. Shimon (or, as some say, R. Yehoshua b. Levi) ruled: One makes [the additional wall of the width of] a “loose tefach” [i.e. slightly more than a tefach] and places it within three tefachim of the wall, since whatever is less than three tefachim from the wall is regarded as joined to the wall.


According to this gemara, the third wall may consist of a piece of material slightly larger than a tefach placed at a right angle to one of the walls. In total, the lavud gap and the piece of wall together constitute a majority of a valid mechitza (four out of seven tefachim).  It would look like this diagram:





            In addition, the gemara that follows brings three opinions regarding whether one must add a tzurat ha-petach to the third wall. The Rishonim discuss this matter in great depth. The Shulchan Arukh (630:2) concludes:


Regarding the walls of a sukka: If there are two [walls] at a perpendicular angle, one should take another wall, slightly wider than a tefach, and place it within three tefachim of one of the walls. Then one places a vertical beam opposite that tefach and makes a doorway and place a cross beam above it and above the tefach [of wall] – and [the sukka] is valid…


According to the Shulchan Arukh, in addition to the piece of wall slightly more than a tefach long and ten tefachim high placed within three tefachim of the wall, one must add a doorway, a tzurat ha-petach, comprised of a vertical beam and cross beam.  (The Chazon Ish [Yoreh De’ah 172:2] writes that this tzurat ha-petach should be comprised of two vertical beams, one next to the tefach of wall and one across from it.)




 The Acharonim debate whether this tzurat ha-petach should extend to the end of the opposite wall (Chazon Ish) or whether it must merely extend three additional tefachim, completing a seven tefachim wall comprised of a tzurat ha-petach, a tefach of wall, and less than three tefachim of space (see Sha’ar Ha-Tziyun 3).  



Some require the tzurat ha-petach to enclose an area of four tefachim (totaling at least eight tefachim), as the narrowest doorway is at least four tefachim wide. 


In addition, the Rema rules that one may count the sekhakh, which extends from the end of one’s tefach of wall until the opposite wall, as a tzurat ha-petach. The Mishna Berura (11) cites the Magen Avraham, who suggests that one must place a cross beam specifically for this purpose, and may not rely upon the sekhakh. The Mishna Berura concludes that one may follow the lenient opinion of the Rema. 


Some Acharonim insist that this extra doorway is only a rabbinic requirement (Peri Megadim, MZ 630:3 and EA 630:7). 


The second scenario described by the gemara entails two walls parallel to each other (known as a “sukka in the shape of a mavuy [alleyway]”).  In this case, the gemara explains:


R. Yehuda said: A sukka made like an [open] alley-way is valid, and this tefach [wall] is placed in whatever side one pleases. 

R. Shimon (or, as some say, R. Yehoshua ben Levi) says: He makes a strip of slightly more than four [tefachim] and places it within three handbreadths of the wall, since whatever is less than three handbreadths from the wall is regarded as joined to the wall.  But why did you say in the previous case that one “loose tefach” suffices, while here you say that there must be a strip of four tefachim? In the previous instance, where there are two valid walls, a “loose tefach” suffices, but here, where there are no two valid walls, if there is a strip of four tefachim it is valid; otherwise, it is not [valid]…

He answered: I accept the other reading of [the statement of] Rava; in addition [to a board of the size of a handbreadth], the form of a doorway is also necessary.


The gemara explains that in this case, since neither of the two walls is valid because they are not connected, one must place a wall slightly more than four tefachim wide and ten tefachim high within three tefachim of one the walls, totaling a wall of seven tefachim.  In addition, one must construct as tzurat ha-petach, like above, which extends from the four tefach wall until the third wall meets the other wall.





This tzurat ha-petach joins all three walls together. Although the Shulchan Arukh cites a debate whether this tzurat ha-petach is necessary, since the combination of the partial wall and the space add up to the length of a valid wall (seven tefachim), the Mishna Berura (16) rules that one should add this tzurat ha-petach. 


While these scenarios may not sound so common, one who builds a sukka on his balcony may encounter this halakha.  Ideally, one who uses a balcony should use all four walls, i.e., the three walls of the balcony and the outer house wall, as the walls of the sukka.  Often, however, one intends to use the wall parallel to one’s house, as well as one of the perpendicular walls.  In this case, one uses a portion of the house wall and the doorway, which serves as a tzurat ha-petach. 


If so, one should be careful that the doorway to the balcony is at least four tefachim from the perpendicular wall. These four tefachim, in addition to a tzurat ha-petach, combine to form the third wall. If the doorway is towards the edge of the balcony, within four tefachim of the perpendicular wall, then the sukka would be invalid when the door to the balcony is opened, as the third wall must have at least four tefachim of wall, or at least a more than a tefach of wall joined with less than three tefachim of space, in order for the added tzurat ha-petach to complete the third wall. Furthermore, it may be prohibited to open and close the door on Shabbat and Yom Tov, as it violates, through validating and invalidating the sukka, the labors of boneh and soter (Shemirat Shabbat Ke-Hilkhata p. 24 ft. 115; see also R. Tzvi Pesach Frank’s Mikra’ei Kodesh 1:11).


            The Rishonim derive from these cases that at least two of the walls of the sukka must connect at a perpendicular angle. The Rishonim (Rif, 2b; Ran s.v. se-amar, etc.) refer to this as “de-areivan” – the two walls must be connected. They may connect physically or through lavud, i.e., being within three tefachim of each other. A tzurat ha-petach at the corner will not suffice.


            In addition, the Rishonim, based upon a passage in the gemara, discuss what percentage of the walls of the sukka may be incomplete, consisting of gaps, windows, or doorways.  When one constructs the third wall in the manner described above, the third and fourth wall are certainly comprised of more empty space than physical wall. This is called merubeh ha-omed al ha-parutz – the area of gaps is larger than the area of wall material. What about the other two walls? Must the majority of the other two walls be comprised of solid material?


Merubeh Ha-Parutz al Ha-Omed


Many people incorporate windows and doors into their sukkot. Others leave gaps in between multiple wooden planks, which combine to form a wall. Even if one’s wall is more than seven tefachim long, how much of the wall can be incomplete?


The gemara (7a) contrasts the laws of mechitzot for Shabbat and Sukkot:


The [law relating to] Shabbat is more [stringent] than that of sukka, in that the [wall for purposes of] Shabbat is valid only if its standing portion is more than that which is broken, which is not the case with the sukka.


In the laws of Shabbat, a reshut ha-yachid, within which one may carry on Shabbat, must be surrounded with four walls, of which the halakha requires omed merubeh al ha-parutz (Eruvin 15b; Shulchan Arukh 362:4). In other words, at least half of the sum total of the mechitzot must be composed of solid material. A wall made up of solid strips or wires within three tefachim of each other (lavud) is considered to be entirely solid (omed). Furthermore, although slightly less than half of the partition may be composed of windows, entrances, and holes, a gap of over ten amot invalidates the entire partition and one may not carry within this area. One may close a gap of ten amot with a tzurat ha-petach, consisting of two vertical posts (lechi), each ten tefachim high, and a horizontal beam placed across the posts (kora). While most Rishonim believe that one may always close a gap wider than ten amot with a tzurat ha-petach, the Rambam permits using a tzurat ha-petach to close a gap of more than ten amot only if the majority of the partition is composed of solid material (omed merubeh) (Shulchan Arukh 362:10). 


            Regarding the laws of sukkot, the gemara cited above implies that the open area may be greater than the standing part (parutz merubeh al ha-omed). The Rishonim, however, disagree as to how to understand this passage. 


Some (Rashi s.v. mah; see Maggid Mishneh to Rambam, Hilkhot Sukka 4:12) explain that the gemara refers only to the case, discussed above, in which the third wall of the sukka consists of merely a tefach of solid material. However, the first two walls most certainly must be omed merubeh al ha-parutz. 


The Rambam (Hilkhot Sukka 4:12) disagrees and rules that a sukka which has many doors and windows, even if parutz omed al ha-merubeh, is valid. Rabbeinu Yerucham (Toldot Adam Ve-Chava, nativ 5, chelek 1) concurs, adding that even if the standing part of the sukka is spread along the wall and there is no continuous seven tefachim, the sukka is valid! He cites his teacher, R. Avraham ben Ishmael, who insists that if, overall, there is more solid wall than gaps, the seven tefachim of the wall need not be continuous. However, if, overall, there are more gaps than solid wall, then in order to validate the wall, there must be seven continuous tefachim of wall. The Ritva (s.v. amar) disagrees with this leniency and validates the sukka only if each of the two walls has seven tefachim of continuous wall adjoined at a right angle.


Seemingly, one might suggest that the Rishonim disagree as to whether the Torah demands that the sukka be enclosed by mechitzot, in which case the sukka must be omed merubeh al ha-parutz, or whether the gemara simply requires shnayim ke-hilkhatan, two valid mechitzot, regarding which the Rishonim disagree whether the seven tefachim which compose these mechitzot must be continuous, or whether they may even be spread throughout the wall. 


            The Rishonim also disagree regarding a gap of ten amot or more in the sukka.  While the Rosh (1:8) maintains that one if one transforms this gap into a tzurat ha-petach, the sukka is valid, the Rambam (4:12) will only permit a tzurat ha-petach for a gap more than ten amot if the overall ratio of the sukka is omed merubeh al ha-parutz (see Chiddushei Ha-Rav Chaim Ha-Levi, Hilkhot Shabbat 16:16).


            The Shulchan Arukh (630:5) rules leniently and validates the sukka even if the two full length walls are parutz merubeh al ha-omed. The Taz (6) and Magen Avraham (6) rule strictly, in accordance with Rashi, as does the Mishna Berura (22) and the Chazon Ish (75:13). The Mishna Berura (23) cites a view which allows the seven tefachim of the two original walls, the shenayim ke-hilkhatan, to be composed of one piece of at least four amot long, along with other pieces. In his Sha’ar HaTziyun, he cites those who insists that all seven tefachim be continuous. Finally, a gap of less than three tefachim, lavud, is considered to be omed and does not constitute a gap.


            Regarding a gap of over ten amot, the Shulchan Arukh brings both the Rosh and the Rambam cited above.


Needless to say, due to the complexity of these cases, the Rema (5) notes that it is customary (when possible) to construct the sukka from complete walls, without relying the above leniencies.  Similarly, the Mishna Berura (630:28) cites R. Yitzchak Gi’at, who claims that it is a mitzva min ha-muvchar to have three complete walls, without any breaks.