631 - תרלא סוכה שחמתה מרובה מצלתה ויתר דיני הסכך ובו י"ב סעיפים

A Sukkah Whose Sunlight Exceeds Its Shade and Other Laws of the S'chach

1. If the s'chach is a very thin covering, so that there is a lot of open space, but there is not a gap of three tefachim of open space in any one place, and overall, its shade is greater than its sunlight—meaning, the s'chach is more than the open space—then the sukkah is valid.

2. But if the s'chach is not greater than the open space, but rather they are equal, it is invalid.

This is because the sunlight that enters through the open spaces in the s'chach, when it reaches the floor of the sukkah, spreads out more than it does above, in the air of the s'chach.

It turns out that at the bottom, on the floor of the sukkah, its sunlight is greater than its shade.

3. However, if at the bottom, on the floor of the sukkah, its sunlight and shade are equal, it is valid.

This is because it is known that above, in the s'chach, the open space is less than the s'chach, and its shade above is greater than its sunlight. This is considered proper s'chach.

4. If the majority of the s'chach has more shade than sunlight, even by a small amount, and the open space is very minimal, but in a minority of the s'chach its sunlight is greater than its shade by a small amount, so that if you combine the sunlight and shade of all the s'chach together, its shade is greater than its sunlight by a small amount—the sukkah is valid.

It is permitted to sit even under the minority of the s'chach where its sunlight is greater, since it is nullified in relation to the majority of the s'chach where its shade is greater.

However, if the minority of the s'chach where its sunlight is greater measures seven tefachim by seven tefachim, which is the minimum size of a valid sukkah, one should not sit under it.

This is because it is considered a significant area and is not nullified in relation to the rest of the s'chach where its shade is greater.

5. Ideally, the s'chach should be made light and sparse, so that the large stars can be seen through it at night.

After the fact, even if it was made as thick as a house, so that no rays of sunlight can be seen through it, it is valid, as long as rain can still fall through it.

But if the s'chach is so thick that rain cannot fall through it, it is invalid.

This is because it is only called a sukkah if it provides protection only from the sun. But if it also protects from rain, it is not called a sukkah, but rather is like a house.

6. If the s'chach is uneven—meaning, some of it is raised a bit higher and some is a bit lower—even though because of this its sunlight is greater than its shade, it is valid.

Since if the sun were to stand in the middle of the sky, directly above every person’s head, its shade would be greater than its sunlight, it is not invalidated because of sunlight that comes from the side at an angle.

7. When does this apply? When the height between the raised and lowered parts is less than three tefachim, for anything less than three tefachim is considered lavud, and they combine to be considered one s'chach.

But if there are three tefachim between them, they do not combine, and this is not considered s'chach at all.

If the width of the raised s'chach is the size of a roof—that is, one tefach by one tefach or more—and it is aligned directly above the open space below, even if there is more than three tefachim between them, it is valid.

This is because we view the raised part as if it descends downward and is placed in the open space beneath it.

This is only if the width of the open space is equal to or greater than the width of the raised part.

But if it is less than that, or if the raised part is not exactly aligned above the open space beneath it, so that if it were to descend straight down, part of it would touch the lower s'chach, we do not view it as if it descends.

All these measurements are halacha l'Moshe miSinai (a law given to Moshe at Sinai).

8. If there are reeds extending behind the sukkah, and two walls continue along with them—for example, behind the middle wall of the sukkah, reeds from the s'chach protrude, and they have the minimum size of a sukkah, that is, seven tefachim by seven tefachim, and their shade is greater than their sunlight, and they have three walls: the middle wall of the sukkah and both long walls that continue with them—this is a complete sukkah and is valid, even though the middle wall was not made for it, but for the main sukkah.

9. Similarly, if reeds protrude from the s'chach toward the fourth side of the sukkah, which is open and has no wall, and one wall continues from the sukkah along with these reeds, and they have the minimum size for a sukkah, this area is also considered part of the sukkah, and it is permitted to sit there, even though there is only one wall.

Even if the owner of the sukkah made it clear that his intention was to make the entire sukkah with the long walls that continue along the entire length of the s'chach—for example, after making one long wall along the entire s'chach, he made the opposite wall longer than seven tefachim—we do not say: "Since it would have sufficed for the third wall to be only seven tefachim, and he made it longer, he has shown that he intends to extend the walls with the s'chach, and not to sit under the s'chach that is open and does not have two walls continuing with it. If so, this wall that continues with these protruding reeds is not considered part of the sukkah at all, but stands on its own, and these reeds have only one wall, that is, the wall that continues with them."

We do not say this, because the making of a sukkah does not require intent, as will be explained in siman 635.

It is as if he did not reveal his intent at all, and all the s'chach is valid with this short third wall, even though it does not extend along the entire length of the s'chach as the opposite wall does, as explained in siman 630.

10. It has already been explained above that if one covered the sukkah with invalid s'chach and with valid s'chach, and they are not mixed together, but each is placed separately on the sukkah, side by side, it is not necessary for the valid s'chach to be the majority over the invalid s'chach; even if they are half and half, the sukkah is valid.

This is a halacha l'Moshe miSinai: the s'chach required for the sukkah does not need to be a majority of valid material, but only half the s'chach.

This is provided that the invalid s'chach does not measure four tefachim in one place in a large sukkah.

A Sukkah Whose Sunlight Exceeds Its Shade and Other Laws of the Schach

11. Even if the valid schach is light and sparse as is its law, so that the stars can be seen through it, and the invalid schach is such that the stars cannot be seen through it—how so? For example, if one covered the sukkah with spits, which are invalid for schach, and left a space between each spit equal to the width of a spit, and placed valid schach, light and sparse as is its law, in those spaces, it turns out that the invalid schach is greater than the valid schach in terms of the length of the valid schach through which the stars can be seen. Nevertheless, since the length and width of the area covered with valid schach is equal to the length and width of the area covered with invalid schach, this sukkah is valid according to the Torah. However, since it is impossible for a person to precisely fill all the air between each spit with valid schach so that there is not even the slightest bit of air between the spit and the valid schach, it turns out that the invalid schach is greater than the valid schach, for there is only the width of a spit between each spit, exactly, and even this space is not completely filled with valid schach, but some air remains between it and the invalid schach. Therefore, this sukkah is not valid unless one increases the valid schach slightly and places it over the invalid schach, so that all the air between the spits is certainly covered. Similarly, if the spits are placed lengthwise along the sukkah and the reeds of the valid schach are placed crosswise, that is, across the width of the sukkah, then necessarily, if the ends of the reeds are not placed on the spits, they will fall to the ground. Thus, it is certain that all the air is covered, and not even the slightest bit of air remains between the spits and the valid schach.

12. A house roofed with boards that do not have plaster on them (meaning a layer of clay that is placed on them), and one wishes to make it valid to sit under them for the sake of a sukkah—since these boards are invalid for schach, even if they are not four tefachim wide, because they were not placed here for shade but for dwelling—how does one make them valid? He removes one board from between every two and places valid schach in its place, and again removes one board and places valid schach in its place, and the entire sukkah will be valid.