Q&A: Bent Wall
Bent Wall
Question
Hello, and many thanks.
I have a sukkah that is 2 meters high and stands adjacent to a roof. The roof is 2.5 meters high and half a meter wide. (If the roof were 2 meters high, this would be a classic case of a bent wall.) Is the sukkah kosher?
Answer
I’m not sure I understood the diagram. Do you mean that there is a roof protruding from the house by half a meter at a height of 2.5 m, and from the point where it ends there begins a sukkah that does not have two walls and a handbreadth of its own, so it needs the wall of the house as a third wall? I’ll answer based on that diagram.
There are several ways to understand the law of a bent wall. Some understood it to mean that the halakhic wall of the sukkah drops straight down from the edge of the roof. According to this approach, the sukkah is of course kosher.
But there are approaches according to which the halakhic wall rises diagonally (this is a permission based on the triangle formed by wall + roof). According to those approaches, we have here a sukkah with a wall that rises from the bottom of the wall to the edge of the protruding roof, meaning that it is separated from the valid sekhakh by some gap. Seemingly, one must make sure that this gap does not exceed 3 handbreadths (because air invalidates with 3 handbreadths even at the side). For this, one has to do a trigonometric calculation of the distance between the diagonal and the sekhakh. If you do the calculation, you get a distance of 10 cm, which would seemingly be kosher. Except that even if we say that the distance is less than 3 handbreadths (as indeed comes out), there is here a problem of applying one halakhic fiction on top of another, since the lavud from the sekhakh to the halakhic wall connects to a wall that does not actually exist there (it is a halakhic diagonal). And according to the approaches of the medieval authorities (Rishonim) who do not say that one halakhic fiction can be built on another (as Rabbi Akiva Eger proves), it seems that this would be invalid.
Bottom line, there is here a double doubt: whether the halakhic wall is according to the first approach or the second, and even if you conclude that we follow the second approach, there is still the question whether we say that one halakhic fiction can be built on another.
Therefore there is room to be lenient, but I would avoid relying on it if possible.
Happy holiday.
Discussion on Answer
Very nice. But one question: when speaking about the distance from the sekhakh to the diagonal, you meant the line from the sekhakh that is perpendicular to the diagonal, right? In other words, the shortest distance between the edge of the sekhakh and a point on the diagonal. Is it clear that this is how one measures in a sukkah? Maybe one still measures the “distance” in a line going upward from the sekhakh to the roof?
And what does it help that there is a point where the distance is short, if say you have a diagram like this ₪< where the left sign marks an area of valid sekhakh and the triangle (in the same plane) is the shape of the roof—do you measure the distance to the triangle’s vertex, or horizontally at each point?
The distance from the sekhakh to the roof is half a meter, and the gap there does not interfere with the sukkah. So it is clear that this is not the relevant gap. There is no need to close it, and therefore the rule of lavud would not be invoked there.
The distance of 10 cm that I calculated is along a straight continuation of the sekhakh until the diagonal (and not perpendicular to the diagonal). The perpendicular distance is of course even shorter, so clearly there is no problem.
Thanks. I mistakenly thought that the half-meter gap from the sekhakh to the roof was relevant, and that it is not considered empty space inside the sukkah but rather the ordinary distance between the sekhakh and the wall. (I’ll also admit, to my embarrassment, that I didn’t calculate the 10 cm before asking; I just relied on the weak analogy that to calculate along a straight continuation, similar triangles should seemingly be enough and trigonometry shouldn’t be needed. But now I see that indeed the ratio of half a meter to two and a half is like the ratio of ten cm to half a meter. And really, it would have been simpler to calculate than to infer and ask, etc.)
Another solution, and easier to carry out, is to add invalid sekhakh at the height of the sukkah, so that the diagonal will relate to the lower sekhakh.
I just now thought that if you can lower some kind of mat (even made of material invalid for sekhakh) from the edge of the roof to the edge of the valid sekhakh, that would solve the problem.