In contemporary measurements a tefach, according to the Chazon Ish, is 9.28 centimeters. According to Rav Avraham Chaim Noeh it is 7.84 centimeters. The height of ten tefachim according to the Chazon Ish is thus 98.2 centimeters; according to Rav Avrohom Chaim Noeh it is 78.36 centimeters. The measurement of seven tefachim according to the Chazon Ish is 68.74 centimeters; according to Rav Avraham Chaim Noeh it is 54.85 centimeters.2. What is the maximum height for a succah?The measurement of an amoh according to the Chazon Ish is 57.6 centimeters. According to Rav Chaim Noeh it is 48 centimeters.
A succah which is higher than twenty amos is prohibited. This halachah applies regardless of the other dimensions of the succah, whether large or small. Also the fact that the walls reach the s'chach or not would also have no bearing upon this halachah (Shulchan Aruch, section 1).3. Would there be any preference to make the succah walls of temporary materials, i.e. not making the succah of walls as strong as those of a regular house? Likewise, perhaps the succah should not be made out of a room of a regularly contructed house due to the requirement of using a temporay dwelling (diras arai)?The Gemoroh derives this as follows. It says in the Torah "You shall dwell in succahs for seven days." The Torah is telling us, "all seven days go out from your permanant dwelling and live in a temporary one." Up to a height of twenty amos a person may make a house in a temporary manner, but higher than twenty amos no one would make a temporary house, but only a permanant one (Gemoroh 2b in the name of Rovoh). This is why it states the word "taishvu" (to reside) and not "taduru" (to dwell) (Shaar Hatzion section 4).
It is permissible to make the walls of any kind of material, even the very strongest. It would also be permitted to build the succah in a room in the house. For the requirement of the Torah that it should be a temporary dwelling is fulfilled as long as it is able to be made in a tempory way even if in fact it is made of very solid material.Next Chapter