The Walls of the sukka

  • Rav David Brofsky

the laws of THE FESTIVALS



by Rav David Brofsky


Shiur #15 – The Walls of the Sukka


Last week, we discussed the dimensions of a valid sukka.  We learned that one should optimally construct a sukka of at least three valid walls, each at least seven tefachim long and ten tefachim high.  We noted that through employing the principles of lavud and gud asik mechitza, one may even use a wall of slightly over seven tefachim and suspend it within three tefachim of the ground.  When building a sukka only ten tefachim high, one can even use a solid material slightly over four tefachim long and suspend it within three tefachim of the ground and within three tefachim of the sekhakh. 

We also learned that a sukka should not be higher than twenty amot from the ground.  In addition, the minimum area of a sukka should be at least seven tefachim by seven tefachim, enough space for one’s head, the majority of one’s body, and a small table. 

 Finally, we discussed how, when necessary, one can even construct a sukka from two full walls (each measuring a minimum of seven tefachim) and one partial wall.  The Talmud distinguishes between a case in which the two complete walls are adjacent to each other, at a right angle, or parallel to each other.  Through employing the principles of lavud and by using a tzurat ha-petach, the Talmud and the Rishonim describe how one can construct such a sukka.  In this case, the sum total of the area of the third and fourth walls is parutz meruba al ha-omed (there is more empty space than solid material), the Rishonim disagree as to whether the first two walls must be omed meruba al ha-parutz (there must be more solid material than space) or not.  We concluded that it is customary, when possible, to construct a sukka of at least three complete walls in order to avoid the complexities of these halakhot. 

 This week, we will study the laws relating to the walls themselves: what material may be used for the walls, how sturdy must the walls be, ma’amid be-davar ha-mekabel tuma, and using part of the roof as one’s wall (dofen akuma).

 A Wall that Cannot Withstand a Ruach Metzuya - Canvas Sukkot

 The mishna (12a) teaches that “all materials are valid for the walls.” Indeed, throughout the masekhet, the gemara describes constructing walls from materials that one cannot use for sekhakh (2a, 21b, 23a, 24b).  Interestingly, the Or Zaru’a (Hilkhot Sukka 289:2; see also Hagahot Asheri 1:24) cites a Yerushalmi that warns that one may not construct a sukka from materials that are mekabel tuma (objects that potentially may become tamei), i.e., materials that may not be used for sekhakh.  This position is troubling, not only because the gemara consistently implies that one may use objects that are mekabel tuma for walls, but also because the Yerushalmi itself (1:6) implies the opposite!

 The Rishonim and the Shulchan Arukh (630:1) rule that one may construct the walls of a sukka from any material.  Although the Bach suggests that one should refrain from constructing the walls from materials that one may not use for sekhakh, the Acharonim reject this stringency.


Although the Talmud permits one to construct the walls of the sukka from any material, discussing scenarios in which one may use an animal (Sukka 23a) or one’s friend (Eruvin 44a-b) as a wall, the gemara establishes certain limitations to this principle.  For example, the gemara (24a) teaches that the walls of the sukka must be able to withstand a common wind (ruach metzuya) without moving.


If he makes his sukka between trees so that the trees form its walls, it is valid.  R. Acha b. Yaakov said: A partition which is unable to withstand a normal wind is not a valid partition.  Have we not learned: If he makes his sukka between trees, so that the trees form its walls, it is valid - but do [the trees] not sway to and fro? We are dealing here with solid [trees].  But are there not the swaying branches? [It refers to] where he plaited it with shrubbery and bay-trees. 

The gemara describes how one may use trees as the walls for one’s sukka as long as the trees are solid and firmly rooted and the branches are tied down.  Apparently, R. Acha b. Yaakov understands that although the wind will not knock down the walls of the sukka, walls that move cannot be considered halakhically valid walls (Sha’ar Ha-Tziyun 45). 

 How much must the walls move in order to be disqualified? Furthermore, what is the basis for this halakha?

Some (Chazon Ish, Hilkhot Eruvin 13:6) suggest that a mechitza that cannot withstand a ruach metzuya is not valid only when the walls move in a fashion that disqualifies them as walls, that is, they fall or they sway more than three tefachim in either direction.  Earlier authorities, such as R. Moshe di Trani (Mabit; 1505-1585; Kiryat Sefer, Hilkhot Sukka, ch. 4), agree.  According to this approach, one should be permitted to construct a sukka in an area without wind.  Indeed, the Be’er Heitev (630:10) cites those who permit building a sukka from thin sheets in a courtyard surrounded by walls.  The Chazon Ish (Orach Chaim 52:14) is inclined to agree with this conclusion.

Others disagree and understand that a wall that can be swayed by the wind is simply not considered a halakhically valid wall.  Many Rishonim (see Ritva, Sukka 24b, s.v. amar, for example) explain that even if the wind moves the walls without causing it them to fall, they are disqualified.  Some bring a proof from the following gemara (22b):


If one erects his sukka on the top of a wagon or on the deck of a ship, it is valid.  According to whom is our mishna? According to R. Akiva, as it has been taught: He who erects his sukka on the deck of a ship, R. Gamliel declares it invalid and R. Akiva valid.  It happened with R. Gamliel and R. Akiva when they were journeying on a ship that R. Akiva arose and erected a sukka on the deck of the ship.  On the morrow, the wind blew and tore it away.  R. Gamliel said to him: Akiva, where is your sukka? Abayye said: All are in accord that where it is unable to withstand a normal land breeze, it is nothing; if it can withstand an unusually [strong] land breeze, all are in accord that it is valid.  Where do they dispute? Where it can withstand a normal land breeze, but not a normal sea breeze; R. Gamliel is of the opinion that the sukka must be a permanent abode, and since it cannot withstand a normal sea breeze, it is nothing, while R.  Akiva is of the opinion that the sukka must be a temporary abode, and since it can withstand a normal land breeze, it is valid.


According to this passage, R. Akiva erected the sukka on the ship knowing that a normal sea breeze might topple his sukka.  In other words, he did not refrain from building the sukka on the ship lest it fall.  Apparently, whether a wall can withstand a normal land breeze defines whether it is a valid mechitza.  Therefore, even if one builds a sukka that can withstand a normal land breeze in a place with a stronger breeze, which is likely to topple the sukka, the sukka is still valid.   

            If the strength of the walls, and not whether practically they will or will not sway in the wind, determines the validity of a sukka, then even if a sukka which cannot withstand a ruach metzuya is built in an enclosed area or an area without wind, it should still be invalid, as the mechitzot simply do not qualify as valid walls (Magen Avraham 15). 

            R. Aryeh Pomeranzyck (Emek Berakha, Sukka, 19) and R. Tzvi Pesach Frank (Mikra’ei Kodesh, Sukka 1:2) discuss this issue in depth, as does R. Moshe Feinstein (Iggerot Moshe, Orach Chaim 5:40:2), who explains that this law is based is on the principle of teshvhu ke-en taduru - one’s sukka should be like one’s house, which does not sway in the wind.   

The Shulchan Arukh 630:10 rules in accordance with the gemara cited above:


One who makes is sukka between the trees, so that the trees will form its walls - if [the trees] are strong or if he tied them and strengthened them so that the wind should not constantly move them… [this sukka] is valid. 

Therefore, one should not eat or sleep in a sukka whose walls sway.  While the Chazon Ish identifies three tefachim as the amount of swaying which invalidates a sukka, R. Ovadia Yosef (Yechavveh Da’at 3:46) insists that any swaying at all disqualifies the sukka.  R. Moshe Feinstein (Iggerot Moshe, Orach Chaim 5:40:2) writes that slight swaying (nidnud ketzat) may not disqualify the sukka.   

In addition to fearing that the walls may sway in the wind, the Tur (630), citing Rabbeinu Peretz, raises another concern. 


It is improper to make the walls from sheets of flax... even if he tied them securely [because] sometimes they become unfastened, without his being aware, and the result is a wall that does not stand in the wind. 

Rabbeinu Peretz rules that one should not even use walls made from sheets if they are tied down, lest they become detached.  Rabbeinu Peretz apparently did not consider these sheets to be inherently invalid to serve as walls for the sukka; rather, he is concerned that they may become unfastened.  The Shulchan Arukh (630:10) cites this view.  Therefore, although this restriction is not recorded in the gemara, normative practice prohibits making the walls of the sukka from sheets, lest they become unfastened.   

Many contemporary authorities note the popularity of sukkot constructed from canvas, and at times plastic, walls.  Seemingly, according to what we learned above, even if the walls do not sway in the wind, one should still refrain from constructing a sukka from sheets.  R. Moshe Shternbuch, in his Mo’adim U-Zemanim (1:84) explains that in his view, slight movement of the walls does not pose a problem; therefore, if one secures the sheet tightly all around the frame, the sukka is valid.  He still insists that one should preferably not rely upon this, as does R. Moshe Feinstein (Orach Chaim 5:40:2), who notes that this leniency does not appear in any of the commentaries on the Shulchan Arukh.  Some suggest that if the canvas walls are attached tightly and fitted with metal rings, there is no fear that they will become detached, and they may be used (Sukka Ke-Hilkhata, ch. 4, n. 2; Cheiko Mamtakim 630:42).  Although reasonable, one might still insist that the Shulchan Arukh intended to discourage the use of a fabric for sukka walls in all cases.  R. Moshe Feinstein (ibid.) writes that one should not misinterpret the availability of canvas sukkot as an endorsement of their validity.  Interestingly, it is worth noting that the Arukh Ha-Shulchan (530:32) writes that be-diaved, if one tied the canvas walls, the sukka is valid. 

In recent years, the practice of using horizontal poles or tightly strung strings and relying upon the halakha of lavud has gained great popularity.  As we discussed previously, as long as there are no uninterrupted gaps of more than three tefachim for a height of ten tefachim, the walls of the sukka are valid, even though the majority of space is not filled with solid matter.  Assuming that three tefachim is minimally 24 cm and ten tefachim is between 80 and 100 cm, one should place a horizontal pole or string at approximately 24 cm intervals, until three “walls” of 80 - 100 cm are constructed.  The Shulchan Arukh even mentions this practice, which originally appeared in the Hagahot Rabbeinu Peretz to the Semak.  He writes, “One who wishes to make [his walls with] sheets should preferably weave mechitzot of reeds less than three tefachim apart.”  

This practice is also relevant for those who construct sukkot on their balconies, often using the picketed balcony as the walls. 

            Not all agree that one can construct a sukka from horizontal strings within three tefachim of one another.  The Magen Avraham (630; see also Mishna Berura 7), based upon the view of Tosafot (Sukka 16b, s.v. be-fachot), writes that unless one encloses the entire sukka, all four walls, with these walls, one cannot rely upon lavud for all three walls of one’s sukka.  The Eliyah Rabba (19) writes that one should not be concerned with their view in our case, as the true halakhic wall is the canvas wall, and the lavud wall is added as a stringency (see also Sha’ar Ha-Tziyun 49).   

Supporting the Sekhakh on a Davar Ha-Mekabel Tuma 

            The walls of the sukka serve two functions.  First and foremost, they are the mechitzot of the sukka.  As we discussed last week, a sukka must be constructed of at least three walls, or two walls and a small section.  Second, the walls may (although not necessarily) support the sekhakh, which must cover the entire sukka.  In this second context, the mishna teaches:


If a man supports his sukka with the legs of a bed, it is valid.  R. Yehuda said: If it cannot stand by itself, it is invalid.


Why does R. Yehuda prohibit placing the sukka (that is, the sekhakh) on the legs of a bed? The gemara continues:


What is the reason of R. Yehuda? — R. Zera and R. Abba b. Mamal disagree.  One says: It is because the sukka has no permanence (mipnei she-ein la keva), and the other says: It is because he supports [the sekhakh] with something which is mekabel tuma. 


The Rishonim offer different explanations for both interpretations of R. Yehuda, and, as we shall see, differ regarding the final halakha. 

            Why does “because the sukka has no permanence” invalidate a sukka resting upon the legs of a bed? In what way does resting the sekhakh on the legs of a bed undermine the permanence of a sukka? The Rishonim offer different interpretations.  Rashi (s.v. she-ein), for example, explains that since the entire sukka rests upon the bed and is therefore mobile, it lacks “permanence.” Some Rishonim (see Tosafot, s.v. she-ein) question how his case differs from a sukka resting on a boat or a wagon (22b), which are also mobile! The Ra’avad (Hasagot Ha-Ra’avad, 10a) adopts an opposite interpretation: This sukka lacks “permanence” because if the bed is moved, the sukka will collapse.   

Why would R. Yehuda not permit one to support the sekhakh on something that is mekabel tuma? Rashi (s.v. she-ma’amida) explains:


Even though we only learned this disqualification regarding sekhakh, since [the ma'amid] supports the sekhakh, it is as if he used that which is mekabek tuma for sekhakh. 

Rashi implies that by supporting the sekhakh with an object that is mekbel tuma, it is as if this object was used as the sekhakh.  This interpretation is difficult, not only because he implies that this is a problem mi-de’oraita, but also because he views that which supports, or enables, as part of that which is supported or enabled itself!  

            Other Rishonim (Ra’avad, 10a; Ritva, s.v. ve-chad; Ran, s.v. matnitin) explain that the Rabbis prohibited placing sekhakh upon a davar she-mekabel tuma lest one come to use this material as sekhakh.  Some question what the difference is between placing sekhakh upon the legs of a bed and constructing a sukka on the top of a tree, which is also invalid for sekhakh.  The Ra’avad (Hasagot Ha-Ra’avad 10a) suggests that since it is uncommon to use trees, which are attached to the ground and cannot be used as sekhakh, when building a sukka, the Rabbis saw no reason to prohibit “ma’amid” (supporting) on a tree.  Alternatively, the Ramban (Milchamot Hashem 10a) notes that the Rabbis prohibited supporting sekhakh on a material that is invalid for sekhakh; one who builds a sukka in a treetop, however, does not place the sekhakh on the tree, but rather rests the sukka on the tree.   

            The Rishonim differ as to whether the halakha follows the first opinion of the mishna, that of the Chakhamim, who permit supporting a sukka on the leg of a bed, or R. Yehuda.  Furthermore, even if the halakha follows the opinion of R. Yehuda, is that because such a sukka lacks permanence or because the sekhakh rests upon a material which is mekabel tuma?   

The Rambam (see Commentary to the Mishna and note his omission of this halakha in the Mishnah Torah), Ba’al Ha-Ma’or (10a), Ra’avya (631), Maharil (Responsa 83), and others rule like the Chakhamim.  Other Rishonim rule in accordance with R. Yehuda.  While the Rosh (1:1) accepts the opinion that explains that R. Yehuda requires that the sukka have “permanence," the Ramban (Milchamot Hashem, 10a) and many other Rishonim rule that one may not rest the sekhakh upon a davar she-mekabel tuma. 

Interestingly, the Shulchan Arukh appears to rule like the Chakhamim, as he validates a sukka resting upon the legs of a bed (630:3).  On the other hand, elsewhere (629:7), he explicitly expresses doubt whether one may use a ladder, which is mekabel tuma, to support the sekhakh. 

The Acharonim disagree as to how to understand this doubt of the Shulchan Arukh.  The Taz (10) explains that a ladder is not valid for sekhakh because it is more than four tefachim wide, and the Rabbis prohibited using boards more than four tefachim wide (Sukka 14a).  Therefore, the Shulchan Arukh feared that one might confuse using this ladder to support sekhakh and using this actual ladder as sekhakh.  Other Acharonim, including the Magen Avraham, Shulchan Arukh Ha-Rav, and the Chayye Adam, insist that the Shulchan Arukh is expressing his concern that it may be prohibited to support sekhakh on a material that is mekabel tuma. 

The Arukh Ha-Shulchan (629:19) asserts that the halakha is in accordance with the lenient opinion, and that one should follow the opinion that is not concerned with supporting sekhakh upon a material that is mekabel tume’ah.  The Mishna Berura (630:59; see also Sha’ar Ha-Tziyun 60), however, writes that although the law is really in accordance with the more lenient opinion, one should preferably act stringently regarding this matter. 


            Interestingly, the Shulchan Arukh implies that all agree that one may rest the sekhakh upon a material that is not mekabel tuma that is supported by a material which is mekabel tume’ah, known as “ma’amid de-ma’amid.” The Shulchan Arukh (629:8) permits one to attach the wooden beams of the sukka with metal nails, which are mekabel tuma.  Many Acharonim (see Mishna Berura 629:26 and Sha’ar Ha-Tziyun 51) understand that even those who are stringent regarding ma’amid al davar she-mekabel tuma certainly permit one to place sekhakh on materials that are not mekabel tume’ah but are supported by material that is mekabel tume’ah.  The Chazon Ish (143:2) disagrees, and to this day his students use only wooden pegs, which are not mekabel tume’ah, in constructing the sukka. 


In practice, it is customary not to be concerned with ma’amid de-ma’amid and to construct sukkot with metal frames.  However, many avoid placing sekhakh directly upon materials that are mekabel tume’ah.  Rather, they place wooden beams above the metal horizontal beams of the frame, and place the sekhakh on the wooden beams. 


Dofen Akuma - Using Part of the Roof as a Wall


            We discussed above the materials and physical viability of the sukka walls, as well as their relationship to the sekhakh.  We will conclude with a brief discussion of a sukka wall comprised of a wall and part of the roof.  The mishna (17) teaches:


If [the roof of] a house is breached, and he placed a sukka-covering over it, if there is a distance of four cubits from the wall to the covering, it is invalid. 


The Mishna describes a case in which the middle of a roof is breached.  The person wishes to put sekhakh over the hole, and rely upon the walls of the house to function as the walls of the sukka.  Part of the roof, however, still extends from the walls of the house until where the sekhakh begins.  The mishna teaches that if the part of the roof is wider than four amot, the walls of the house cannot be relied upon.  However, if the part of the remaining roof is narrower than four amot, then the sukka is valid.  The gemara (4a, 17a) bases this upon the principle of dofen akuma (literally, “a bent wall”).  The Rishonim offer different explanations for this principle.


Rashi (s.v. pesulah) cites two understandings.  He first suggests that the wall and the roof combine, and the end of the roof constitutes the meeting place of the wall and the sekhakh.  This is only possible, he claims, where there is sekhakh pasul at the edge of the roof, as sekhakh pasul can combine and join the wall.  Air, however, cannot become part of the wall, and therefore it invalidates the sukka if there is a gap of three tefachim between the wall and the sekhakh.  He then suggests, but rejects, the possibility that we view the wall as slanting, at a diagonal angle, towards the sekhakh.  In this image, the wall is moved closer to the sekhakh, but the sekhakh pasul remains sekhakh pasul.  .


            The gemara (4a) earlier in the masekhet offers a different application of dofen akuma.


If it was higher than twenty amot... If [he built the ledge] on a side [wall] — if from the edge of the ledge to the wall [opposite] there are four amot, it is invalid; but if the distance was less than four cubits, it is valid.  What principle does he teach us by this ruling? That we apply the rule of dofen akuma (the curved wall)? But have we not [already] learnt it: A house [the middle of whose flat roof] is missing and one placed the valid covering of a sukka upon it, if there are four cubits from the [top of the] wall to the covering, it is invalid; which [shows that] if the distance was less than this it is valid? One might have thought that only there [it is valid], since [each side] is suitable [to serve] as a wall, but here, since it is unsuitable for a wall, one might say that it is invalid.  [Therefore,] we were taught [that even here the principle is applied].


In this case, a sukka was built improperly over twenty amot high.  In an attempt to salvage part of the sukka, the person builds a platform along the corner-edge of the sukka, so that the distance between the sekhakh and the elevated platform is less than twenty amot.  However, only two of the walls join the platform to the sekhakh.  In order to validate the sukka, he needs to somehow make use of the opposite, third wall.  The gemara teaches that if the opposite wall is within four amot of the platform, one may apply the principle of dofen akuma.


            Rashi (s.v. pachot) explains that we view the sekhakh raised above twenty amot as a continuation of the wall, bent at a right angle.  In other words, the roof becomes an extension of the wall, meeting the sekhakh at a distance of less than four amot. 


The Ritva (4a) brings another interpretation.  He cites an opinion of Rashi, found in other Rishonim (Ran 2a; Maggid Mishna 4:14) but not in our printed Talmud.  Rashi explains that the opposite wall is bent, diagonally, towards the platform.  In this case, the opposite wall joins the sekhakh kasher and the entire sukka becomes valid.  He adds that according to this interpretation, one may even sit under the sekhakh that is above twenty amot, as it is simply considered sekhakh pasul within a valid sukka! This opinion, of course, is similar to the opinion Rashi rejected previously (4a).  The Ritva then cites another interpretation, attributed to Tosafot, which is similar to Rashi found in our gemara. 


            Interestingly, the Rambam describes the principle of dofen akuma differently when citing these different cases.  Regarding the case in which the sukka was built over twenty amot height (Sukka 41), he writes (Hilkhot Sukka 4:14):


Should one build the bench in the middle [of the sukka], if there are more than four amot from the edge of the bench to any of the sides [of the sukka], it is not acceptable.  If there are fewer than four amot, it is valid.  It is considered as if the walls touch the bench, and the distance from the bench to the sekhakh is less than twenty amot.


Regarding the case in which the roof of the house was breached (17a), he writes:


Where the substance that is unacceptable as sekhakh is at the side, it disqualifies the sukka if there are four amot of it.  [If there is] less than that, the sukka is valid.  For example, a) [the roof of] a house which was opened in the center and sekhakh placed over the opening; b) a courtyard surrounded by an exedra which was covered with sekhakh; c) a large sukka over which was placed a substance that was not acceptable as sekhakh near the sides of its walls.  [In all these cases,] if there are four amot [or more] from the edge of the kosher sekhakh until the wall, it is not acceptable.  If there is less than that amount, we view it as though the wall has been made crooked - i.e., the substance that is not acceptable as sekhakh is considered part of the wall and it is valid.  This concept is a halakha received by Moshe on Mount Sinai.


In the first case, he describes the walls of the house as if they touch the bench or platform, similar to the position of Rashi as cited by the Ritva, or the interpretation Rashi rejected (17a).  In the second case, he describes how the sekhakh pasul becomes part of the wall, similar to Rashi (17a) and Tosafot. 


            The Rambam seems to accept both understandings of dofen akuma! R. Soloveitchik explains that in the second case, the sekhakh pasul can become part of the wall, a principle received from Moshe at Sinai, and “bend” towards the platform, making one long wall.  However, in the first case, the sekhakh pasul cannot become part of the wall, as it is higher than twenty amot, and therefore it must remain sekhakh pasul.  However, we may view the wall on a diagonal angle, as walls are often bent slightly, and validate the sukka (Reshimot Shiurim 4a). 


            The Shulchan Arukh (632:1, 633:6-7) cites both cases of dofen akuma.  He rules (632:1) that one should not sleep under the dofen akuma, if it is more than four tefachim in wide.  At times, this principle may be relevant in a semi-enclosed patio.  If the patio is surrounded, on both sides, with two walls, and an overhang, and less than four amot hangs off the outer wall of the house over the patio, then one can count the wall of the house as the third wall of the sukka.  In this case, one should merely suspend the sekhakh over the patio, and the sukka is valid, even if the fourth, outer “wall” is open.


Next week we will begin our discussion of the laws of sekhakh.