6. The dimensions of the Sukkah:
A. The height:
Minimum height: The Sukkah must have minimum height of 10 Tefachim [82 cm.]. If its height is less than ten Tefach high, it is invalid. The height is measured from the floor of the Sukkah until the Sechach. Even if decorations hang within the ten Tefach space of the Sukkah, it remains valid.
Maximum height: The maximum permitted height that a Sukkah may have is 20 Amos [940 cm.]. This applies irrelevant of the size of the Sukkah, whether it is large or small. This height is measured from the floor of the Sukkah until the Sechach. This applies whether or not the walls of the Sukkah reach the Sechach. If there is more than 20 Amos between the floor and the Sechach, then it is invalid. If there is exactly twenty Amos, then it is valid. If the Sechach is above twenty Amos from the floor, but under the Sechach there is only twenty Amos of space between it and the floor [i.e. the Sechach is in the 21st Ama], then it is valid.
B. The length/width:
A Sukkah must have the minimum size of seven by seven Tefachim [57.2 x 57.2 cm]. If it does not have this minimum size, it is invalid. There is no maximum size for the Sukkah. A round Sukkah must contain the above square dimension within its circle. [The Sukkah must be at least seven Tefachim both in width and length. If it is less than seven Tefachim in either length or width, then even if it contains a total space of 7 square Tefach, it is invalid. For example, a Sukkah that is 20 Tefach by 6 Tefach is invalid.]
Corner areas and rooms in a Sukkah: A Sukkah that contains an extension area [i.e. “corner” in Halacha] that is less than 7×7 Tefachim, then that extension are is invalid, and does not join the rest of the Sukkah. [If either the length or width of the extension area is less than 7 Tefachim, it is invalid. However, one may be lenient to have one’s table situated in the area of this extension, even if it is less than 7×7. Likewise, rooms that are separated with Mechitzos are invalid if they contain a dimension that is less than 7×7 Tefachim. Thus, not only must the entire Sukkah be 7×7 Tefachim, but any area of the Sukkah that is separate from the other areas must also contain a dimension of 7×7 Tefachim.]
The minimum dimensions of a Sukkah is 57.2 x 57.2 centemeters with a minimum height of 82 centemeters, and a maximum height of 938 cm from the floor to the Sechach.
May one put up a Mechitza in a Sukkah?
A Mechitza may only be set up in a Sukkah if it leaves a dimension of 7×7 Tefachim on each side of the Mechitza, otherwise that area that contains less than 7×7 Tefachim becomes invalidated. Thus, when setting up Mechitzos in a Sukkah to separate between men and women, or to separate between diners in a restaurant or hotel, or to separate between people in quarantine, then one must make sure to leave a space of 7×7 Tefachim within each Mechitza.
May one sit near the inside edge of a round Sukkah?
If there is furniture or appliances in the Sukkah, does it diminish from the 7×7 dimension?
Yes. Thus, one must beware that there remains a 7×7 Tefach free space in the Sukkah even after all the furniture and appliances are entered.
Does a Sukkah require a Mezuzah?
A Sukkah is not obligated to have a Mezuzah.
A Sukkah built in a house with a removeable roof: If one’s home contains a room with a retractable roof which is turned into a Sukkah, then based on the above some Poskim learn that the room is exempt from Mezuzah throughout the duration of Sukkos. Accordingly, some Poskim rule that after Sukkos when the roof is replaced one would be required to replace the Mezuzah with a blessing, as otherwise it would be considered Taaseh Velo Min Hasuiy. Other Poskim, however, argue that in truth the removing of the roof does not make the room exempt from Mezuzah, and even if it did one would not be required to replace the Mezuzah after Sukkos being that to begin with it was placed on correctly. Practically, the custom of the world is not to replace the Mezuzah after Sukkos. However, one who desires to be stringent like the first opijnion should remove the Mezuzah after Sukkos and replace it without a blessing.
Room leading into a Sukkah: The door of a room leading into a Sukkah, such as if the Sukkah is inside one’s home on the porch, is obligated in Mezuzah even during Sukkos, as it leads into a home. However, some Poskim rule that on Erev Sukkos the Mezuzah is to be replaced to the right side going into the home throughout the duration of Sukkos, as opposed to on the right side going into the porch. However, according to the second opinion mentioned above, this is not necessary, and so is the custom to not change the position of the Mezuzah.
Sukkah leads to house: A courtyard or backyard entrance that is used as part of a Sukkah remains obligated in Mezuzah throughout Sukkos being that it leads into the home. Nonetheless, if a Sukkah is built in front of the entrance door to the home, the Sukkah is exempt from Mezuzah even though it leads into the home.
 Michaber 633:10; Sukkah 4b and 5b
 See Shiureiy Torah p. 249 that an Ama Sochekes is 49 cm., and accordingly a Tefach Sochakos is 8.17 cm [i.e. 1/48 of a cm times 8.] and by the Shiur Sukkah of 7×7 one should measure with an Ama Sochakos, and the same would apply here Lechumra. Thus, its exact Shiur is 81.7 cm; See also M”B 633:2 and Shaar Hatziyon 633:2 that by Sukkah we follow the stringent approach in the dimensions, either Dochakos or Sochakos, and by the 7×7 dimension we follow Sochakos, and the same would apply here by the ten Tefach dimension; See also Midos Vishureiy Torah pp. 48-57 regarding Ama Sochakos and Dochakos; Piskeiy Teshuvos 633:1; Minchas Chinuch Mitzvah 325 who rules that by Tefachim we don’t apply the extra Dochakos or Sochakos, and this is only done by Amos
Other opinions-Chazon Ish: According to the Chazon Ish, the measurement is 98.2 cm following the 9.82 measurement of Tefach Sochakos. [See Piskeiy Teshuvos ibid]
 See Michaber 633:9-10 and Sukkah ibid and 10b regarding if a) there are Sechach pieces and decorations that go into the ten Tefachim and b) if one dug out the floor of the Sukkah so it reach ten Tefachim.
 Michaber 633:1; Tana Kama in Mishneh Sukkah 2a
Other opinions in Mishneh: Rebbe Yehuda is of the opinion that a Sukkah which is higher than 20 hours is valid. [Mishneh Sukkah ibid]
Other details: Sechach is higher than 20 Amos, but it has pieces of it wwhich reach within twenty: See 633:2; Its inside contains more than than 20 Ama and hung decorations or covered floor with pillows or earth, or platform/Itztaba, which now makes it contain less: 633:3-7
 See Shiureiy Torah p. 249 that an Ama is 47 Dochakos [as opposed to 48 for a regular Tefach], and by the Shiur Sukkah of 7×7 one should measure with the stringent approach of an Ama Sochakos, and the same would apply here Lechumra to measure the twenty Amos as Dochakos. See also M”B 633:2 and Shaar Hatziyon 633:2 that by Sukkah we follow the stringent approach in the dimensions, either Dochakos or Sochakos, and by the 7×7 dimension we follow Sochakos, and the same would apply here by the 20 Amos dimension; See also Midos Vishureiy Torah pp. 48-57 regarding Ama Sochakos and Dochakos; Piskeiy Teshuvos 633:1 writes that its 938 cm accoridng to Grach Nah, taking into account the Dochakos accoridng to Chazon Ish, as he explains there in footnote 2
Other opinions-Chazon Ish: According to the Chazon Ish, the measurement is 1,130 cm following the 9.42 measurement of Tefach Dochakos. [See Piskeiy Teshuvos ibid]
 The reason: The reason for this is because the Sechach is considered to be unable to provide shade when it is more than twenty Amos from the floor.
 Michaber 634:1; Sukkah 2a-3b that the Sukkah must hold the head, majority of and body and table
Does a ledge or step inside of a Sukkah count as part of the 7 by 7 required Tefachim, as is common in porches to have a ledge surrounding it,on which the fence is situated? If the ledge is less than ten Tefachim high, than it counts as part of the 7×7 required Tefachim. If more than ten Tefachim high, it is questionable if it is valid. [See Devar Shmuel 203, brought in Shaareiy Teshuvah 634:3; Bikureiy Yaakov 634:6; Gilyonei Hashas Mahariy Engel Sukkah 16b; Mikraeiy Kodesh Sukkos 1:3; Chelkas Yaakov 3:16; Orchos Rabbeinu 2:220 in name of Chazon Ish; Shevet Halevi 8:148; Hasukkah Hashaleim Miluim 5:6 in name of Rav SZ”A; Piskeiy Teshuvos 634:4]
A Sukkah made with two walls pointing diagonally [like this <]: Some say that it should be viewed as three walls, however the space in the corner which does not contain 7×7 Tefachim is invalid to sit in. [See Chazon Ish Eiruvin 72:5; Piskeiy Teshuvos 634:2]
 See Shiureiy Torah p. 249 that an Ama Sochekes is 49 cm., and accordingly a Tefach Sochakos is 8.17 cm [i.e. 1/48 of a cm times 8.] and by the Shiur Sukkah of 7×7 one should measure with an Ama Sochakos, and the same would apply here Lechumra. Thus, its exact Shiur is 57.16 cm; See also M”B 633:2 and Shaar Hatziyon 633:2 that by Sukkah we follow the stringent approach in the dimensions, either Dochakos or Sochakos, and by the 7×7 dimension we follow Sochakos, and the same would apply here by the ten Tefach dimension; See also Midos Vishureiy Torah pp. 48-57 regarding Ama Sochakos and Dochakos; Piskeiy Teshuvos 633:1; Minchas Chinuch Mitzvah 325 who rules that by Tefachim we don’t apply the extra Dochakos or Sochakos, and this is only done by Amos
Other opinions-Chazon Ish: According to the Chazon Ish, the measurement is 68.74 cm following the 9.82 measurement of Tefach Sochakos. [See Piskeiy Teshuvos ibid]
 The reason: As only this size can hold one’s head, the majority of one’s body, and a table. [Sukkah ibid; M”B 634:1 and Shaar Hatziyon 634:1]
 Michaber 634:2
 M”A 634:1; Taz 634:1; Elya Raba ; Chacham Tzevi ; Mamar Mordechai; M”B 634:1
Other opinions: Some Poskim rule it suffices if the Sukkah contains 7 square Teafch even if there is not Seven Tefach in the width or length. [Bach 634]
 M”A 634:1; M”B 634:1; Biur Halacha 634:1 “Sukkah” in length; See Bigdei Yesha 634; Bikureiy Yaakov 634
Other opinions: Some Poskim negate the ruling of the M”A and rule that an extension of the Sukkah is valid just like the Sukkah itself and does not need to have its own 7×7 dimension. [Chazon Ish 144:6; Orchos Rabbeinu 2:29; See Bigdei Yesha 634; Bikureiy Yaakov 634]
 Biur Halacha 634:1 “Sukkah”, in negation of Derech HaChaim
Other opinions: Some Poskim rule that a if the length of the extension is not 7 Tefachim it is valid, so long as the width is 7 Tefachim, being that one can join the rest of the Sukkah to its legnth. [Derech HaChaim, brought in Biur Halacha ibid; Chazon Ish 144:6; Chelkas Yaakov 3:16; See Piskeiy Teshuvos 634:1]
 Biur Halacha 634:1 “Sukkah” in name of Bikureiy Yaakov
 See Q&A!
 So is implied from Sukkah ibid regarding the inner rooms of the Sukkah of Hilni the Queen which were made for Tzenius purposes; M”A ibid regarding a corner
 Biur Halacha 634:1 “Sukkah” in negation of opinion of Bikureiy Yaakov in his understanding of M”A ibid that only the actualmiddle of the circle is valid
 Piskeiy Teshuvos 634:1 based on ruling of M”A and Poskim ibid who invalidate an extension from a Sukkah being that in that area one does not have a 7×7 space.
 Michaber Y.D. 286:11; See Piskeiy Teshuvos 626:11-12
 The reason: As it is not a place of permanent dwelling. [Shach 286:21; Taz 286:10]
 M”B 626:21 in implication of P”M end of 643; Shaareiy Teshuvah 626:7 in name of Peri Chadash inm Teshuvah; Bikureiy Yaakov 625:4; Kesav Sofer Y.D. 139; Shoel Umeishiv Gimel 2:166; Kaf Hachaim 626:45
 Shaareiy Teshuvah ibid in name of Peri Chadash in Tesuhvah
 Shaareiy Teshuvah ibid in name of Turei Even 14; Mateh Efraim 625:27; Derech Hachaim; Mikdash Me’at Mezuzah 286:37; Kitzur SHU”A 134:10; Aruch Hashulchan Y.D. 286:27; Maharshag 2:75
 Maharshag ibid that even Rabbanom are not Machmir in this; Kitzur SHU”A ibid; Shevet Halevi 2:153; Piskeiy Teshuvos ibid; See Misgeres Hashulchan 134:10 and Piskeiy Teshuvos ibid regarding if the Mezuzah was erected during Sukkos
 Shaareiy Teshuvah ibid
 M”B 626:21
 Bikureiy Yaakov 625:4
 Shevet Halevi ibid; Piskeiy Teshuvos ibid
 M”B 626:21
 Mikdash Me’at Mezuzah 286:37; Salmas Chaim 242; Sefer Hasukkah Hashaleim Pesakim of Rav SZ”A 14