The Mechaber (151:1) says that one may not act with kalos rosh – lightheadedness in the Bais Haknesses. Included in this is the obligation to have a mechitza – partition between the men and women. Reb Moshe zt”l [Igros Moshe Orach Chaim 1; 39] writes that the obligation to have a partition is from the Torah. The purpose of the mechitza is not that the men should not look at the women, because that is anyways prohibited even outside of the Bais Haknesses. Rather the reason for the mechitza is that the men and women should be separate. Being together will lead to talking and touching one another which is kalos rosh.
If the women are in the balcony that alone suffices and no partition is needed. However if they are on the same floor then a mechitza is needed. How tall does the mechitza have to be? Reb Moshe says that it should be shoulder height. Even though the women are still visible it is not a problem, since the purpose of the mechitza is only to make a separation between them as mentioned earlier. Even though they can still be seen it will not lead to kalos rosh. Therefore, if it is three amos high, which is eighteen tefachim, it is a kosher mechitza. According to Reb Chaim Naeh zt”l this equals a little more than four feet and eight inches. According to the Chazon Ish zt”l it is about five feet and seven inches.
Reb Moshe does say that “balei nefesh” – those who are able to go the extra step so to speak, should be stringent and have a mechitza where the women won’t be able to be seen “v’tavo aleyhem brocha” – they should be blessed. This is true especially in places where many women are not careful to cover their hair and it is forbidden to daven in front of them. However l’halacha one can rely the psak of the Aruch Hashulchan that since many women don’t cover their hair it is permissible to daven in their presence. There is a need to protest against the mechitza if it is less than eighteen tefachim, especially since we are dealing with a d’oraisa.
Many chasidishe poskim are of the opinion that if the women can be seen it is not a kosher mechitza at all and it is prohibited to daven in such a place.
The Chasam Sofer says that it is best for the women’s section to be on a balcony. This way the men won’t hear the women davening. The balcony should be in the west side of the Bais Haknesses.1
Prepared by R’ Avrohom Yehoshua Ziskind
1Sources: Igros Moshe, Piskei Teshuvos