15 – Boneh and Soter

01. The Principles of Boneh, Soter, and Makeh Be-fatish

The melakha of Boneh (building) is the melakha through which the Mishkan was constructed. The melakha includes leveling the ground in preparation for erecting the Mishkan upon it and so that people can walk easily in its courtyard. It also includes putting up the walls of the Mishkan, its roofing, and its courtyard gate.

Building anything on the ground or in a house, or adding anything onto a pre-existing structure, is a transgression of a Torah prohibition. Therefore, if one fills in a small hole in a wall or a yard, adds cement or plaster to a wall, or adds water to freshly poured concrete to strengthen it (a process known as curing), he has transgressed a Torah prohibition (Shabbat 102b; 73b).

Any activity that is forbidden on account of Boneh may not be undone, on account of the melakha of Soter (demolishing), assuming that there is a purpose to the demolition. If the act of undoing is destructive, it is rabbinically prohibited. Examples of purposeful demolition include destroying something in order to rebuild it more effectively, digging a hole in the ground in order to lay foundations, or drilling a hole in a wall in order to insert a screw (Shabbat 31b; MT 10:15).

At times, demolition may be purposeful in itself. In such cases, even if there is no intention to build, one still transgresses Boneh. Examples of this include removing extra cement that is stuck on the floor or wall, digging a hole in order to hide things in it, or creating a hole in a wall in order to conceal things there (Shabbat 102b).

An additional melakha connected to building is Makeh Be-fatish (applying the finishing touch). For example, after completing the construction of a house, sometimes there are stones protruding from the wall. They are then often hammered down to make the wall’s surface uniform. Similarly, after completing the manufacture of a metal tool, there are sometimes rough edges remaining that are smoothed out using a hammer. Both of these actions are prohibited on account of Makeh Be-fatish. Toladot of this melakha include fixing broken tools, improving tools whose manufacture is complete, and installing a window to allow air to circulate and light to enter (MT 10:16). There are different opinions in the Gemara regarding whether certain construction-related activities are prohibited on account of Boneh or on account of Makeh Be-fatish (Shabbat 102b). We will not explore these types of disagreements, since the primary purpose of this work is to teach people what is permitted and prohibited rabbinically and by Torah law.

Making cheese on Shabbat is prohibited by Torah law because it causes component parts to solidify and coalesce, in the manner of construction (MT 7:6). Making snowballs or snowmen is also prohibited; but since these do not last, the prohibition is rabbinic.

02. Boneh on the Ground, and Safeguards against it

As we have seen, Boneh includes the prohibition of leveling the ground, whether in order to make it easier to walk on, enable chairs and benches to be placed upon it, or to build upon it. Therefore, one who levels a mound of earth or fills in a hole transgresses a Torah prohibition.

If a yard was flooded by rain, one may not spread sand or gravel over it in order to cover the mud. Since those materials are normally left in the ground, this is considered leveling the ground, a violation of Boneh. However, one may spread straw that is designated for animal food over the mud, since he does not intend to leave it there. This is on condition that the straw is spread with a shinui, such as using the back of a shovel to distribute it. Otherwise, the act of spreading looks like a weekday activity (Eruvin 104a; SA 313:10).

One may cover excrement or saliva with sand, since one who does this does not intend to improve the yard, but only to cover the filth (Beitza 8b; MB 313:55). Similarly, if oil spilled on the sidewalk or the floor, one may cover it with sand to prevent people from slipping. This is on condition that the sand was designated for this purpose and thus is not muktzeh (below 23:3). One may similarly spread salt on ice in order to prevent people from slipping (SSK 25:10).

One may not sweep the yard lest he level indentations and thereby transgress a Torah prohibition. However, if the yard is floored with tiles or pavement, he may sweep it.[1]

One who has clay stuck to his shoes should not try to rub it off against the ground, because he may end up leveling the ground (SA 302:6). Some are not worried about this possibility, and permit rubbing off the clay (Rema, Taz). One who so wishes may be lenient, but it is preferable to be stringent. In contrast, one may rub off the clay against a grate, tiles, or stones even le-khatĥila (MB 302:28).

One should not rub saliva that is on the ground into the dirt with one’s shoes, to avoid leveling the ground. If one finds the saliva disgusting, he may step on it in the natural course of his walking, as long as his intention is not to spread it and level the ground (SA 316:11).

One may not play marbles on the ground lest he level the ground so that the marbles roll smoothly. Similarly, one may not play any game on the ground that requires completely flat ground, lest he end up leveling it. Even if the ground is paved, one may not play there, as there is a concern that one might then end up playing on unpaved ground (SA 338:5 and MB ad loc. 20; MB 308:158). However, one may play on the floor inside one’s home; since all homes today have flooring, we are not worried that, as a result of playing there, anyone will end up playing outside on unpaved ground (SSK 16:5).

Children may play in a sandbox containing fine, dry sand, for as long as the sand is dry, the sand will pour back into any indentations made. However, if the sand is wet enough to make holes in it, one may not to play with it (MB 308:143). Wetting the sand is also forbidden, as it constitutes Lash (MB 321:50). If the sand has not been designated for play it is muktzeh, and thus playing with it is forbidden (SA 308:38; MB ad loc. 144).

[1]. Rif maintains that one may sweep the unfloored ground because one will not necessarily level the ground, and thus if one does so it is unintentional, a davar she-eino mitkaven. Rambam permits sweeping an area that is floored. However, if it is unfloored, he is concerned that one might intend to level the ground. Rosh maintains that even a floored area may not be swept because one may come to sweep an unfloored area and level the ground. SA 337:2 rules in accordance with Rambam, while Rema follows Rosh. However, BHL s.v. “ve-yesh” states that in a place where all homes have flooring, Rosh’s prohibition does not apply. R. Shlomo Zalman Auerbach adds that a paved area outside a house, even if it is not covered by a roof, is considered part of the house, and even the Rema would permit sweeping such an area (SSK ch. 23 n. 10). See below, ch. 23 n. 14 and Harĥavot 23:14:6 regarding why there is no problem of muktzeh when sweeping dust from the floor.

03. Attaching Things to a House or the Ground

Permanently affixing something useful to a house or the ground violates the Torah prohibition of Boneh. Removing such fixtures violates the Torah prohibition of Soter. This is the case even if the attachment is not tight and the objects can easily be detached and reattached, as is the case with hinged or sliding windows or doors. Since these are permanently attached to the house, they become part of it, and installing them or removing them is a transgression of a Torah prohibition. Therefore, even if a room is hot, one may not remove a window from the wall or from its frame (Shabbat 122b; SA 308:9; MB ad loc. 39). Similarly, one may not attach or detach a filter that is screwed onto a faucet, rubber pipes attached to the sink, or light bulbs screwed into their sockets, since their attachment to the house is permanent. Similarly, pounding a nail into the wall or gluing a hook to the wall violates a Torah prohibition, since these additions are permanent (Shabbat 103a; MB 314:8).

One may similarly not attach curtain hooks to a curtain track or the curtains themselves to the hooks on the track. Fastening a curtain rod to brackets that protrude from the wall is also prohibited. Even though all these attachments are loose, since the items are being attached to the building, these actions are prohibited by Torah law. If the rod is not truly attached to the brackets, but rather simply rests upon or inside them and can move back and forth easily, then the rod may be placed on the brackets. In such a case, one may also thread the loops at the top of the curtain through the rod.

If the object being attached to the house or the ground will not last long, the prohibition is rabbinic. For example, it is only rabbinically forbidden to attach a vacuum hook to a wall, since its suction cup will not keep the hook anchored for long.

When something may not be attached to the ground or a house, it is also forbidden to tighten its existing attachment. Therefore, one may not tighten the loose screws of a sink, door handle, or closet handle.

In contrast, objects that are not really attached and do not become part of the house may be put up or taken down. For example, one may hang a picture on a nail, because the picture is not considered part of the wall. If a window breaks and cold wind is blowing through the house, the broken window may be covered with cloth to keep out the wind. This is because the cloth does not become part of the wall, but is placed there only temporarily (MB 313:3 and 315:7; SSK 23:41 and 23:44). Similarly, one may stick papers to a refrigerator using magnets, because the magnets are not considered part of the refrigerator. For the same reason, one may hang a colander over the lip of the sink. Inserting a plug in a socket or removing it is also not considered Boneh or Soter, because the plug is not considered part of the house.[2]

It is self-evident that one may open and close doors, windows, and faucets. This is the case even when the door is not usually opened, or when the faucet in question is the water main, which is rarely shut off. Since they remain attached to the building and this type of opening or closing is the way they are normally used, it is not considered Boneh or Soter. Similarly, one may open and close a porch’s sliding roof that is attached with hinges or that slides on a track, as it is considered the same as a window (Rema 626:3).

It is prohibited by Torah law to use a nail or a screw to reattach a door handle that has fallen off. Reattaching it without a nail or a screw in a way that joins the handles of both sides of the door to each other is rabbinically prohibited, since the attachment is only temporary. In contrast, one may insert one of the two handles into the door without using nails or screws. This is not considered an attachment at all, since the handle is just resting there with nothing to support it. However, there is still a concern that one might forget that it is Shabbat and decide to reattach it properly with nails. Therefore, the door handle should be replaced awkwardly, tilted upward or downward, so there is no concern that anyone will tighten the connection. A handle that has begun to come loose from its attachment to the corresponding handle may not be pushed back into place.[3]

[2]. Some are stringent in the case of a plug that is plugged or unplugged only infrequently, such as a refrigerator plug (Ĥut Shani 36:1). However, it would seem that all plugs should be treated in the same way, since plugs in general are plugged and unplugged frequently. Furthermore, their primary connection is to the electrical appliance, and thus they are not considered part of the wall. (See SSK 13:33, n. 112; Orĥot Shabbat 8:17; Menuĥat Ahava 1:24:20.) However, because a plug is muktzeh, it should be grasped using a shinui.

[3]. If the handle had already fallen off multiple times before Shabbat, and everyone is accustomed to using the door with only one of the two handles attached, one may push that one handle back into its normal place, with no awkwardness (Menuĥat Ahava vol. 3 ch. 23 n. 71). The permissive rationale of attaching it awkwardly is cited in Ĥut Shani 36:4:7. When it is impossible to insert even one handle, one may open the door with the help of a screwdriver or the like (SSK 23:37). Water tanks, septic tanks, and electrical or telephone junction panels boxes are considered part of the building, and thus it is rabbinically prohibited to place a permanent cover on such a structure or to open such a cover. If the tank’s cover has a handle, one may open and close it on Shabbat (Shabbat 126b; SA 308:10; MB ad loc. 42; SSK ch. 23 n. 146).

04. Making a Tent (Ohel)

Making an ohel is a tolada of Boneh. In contrast to the melakha of Boneh, which involves attaching different components, such as stone, wood, cement, and metal, to construct a house or implement, making an ohel does not involve the attachment of various components but the erection of something that separates between different areas. The roof of a tent serves as a barrier between the sky and those who are inside the tent, protecting them from the elements. Therefore, pitching a tent on Shabbat using sheets or other things that are not considered construction materials is prohibited by Torah law if the tent is stable and will last for a long time (at least eight days). This is the case even if one tied no knots and used no screws or nails, but only loops and pegs. Even if he only made a roof or a wall, or even simply added a tefaĥ to an existing roof or wall, he has transgressed a Torah prohibition (Pri Megadim, Mishbetzot Zahav 315:8; MB ad loc. 1; SHT ad loc. 6).

The Torah prohibition is limited to a permanent, durable ohel. The Sages further forbid making a temporary ohel. Therefore, one may not spread a curtain or netting over a bed, whether for privacy or for protection against insects.

Since the critical part of an ohel is the roof, one may not make any sort of temporary roof to protect a person beneath it, even if it is only a tefaĥ wide. But one may put up a temporary meĥitza. For example, one may erect a meĥitza between men and women attending a Torah lecture. However, one may not erect a meĥitza that serves to render something halakhically permitted (meĥitza ha-materet) even on a temporary basis. For example, if a sukka has only two walls, a third wall may not be erected, even if it is temporary, since erecting this meĥitza renders the sukka kosher. Similarly, one may not erect a temporary meĥitza in order to close a gap in an eruv, because this renders the eruv kosher (SA 315:1; below 29:8).

The rabbinic prohibition of making a temporary ohel is limited to the case of a new ohel, but one may make a temporary addition to a pre-existing ohel. Therefore, one who wishes to spread an awning in his garden on Shabbat to protect himself from the sun should make sure to spread it at least a tefaĥ before Shabbat. He may then extend it fully on Shabbat. Similarly, if the beginning of a permanent roof is already in place, one may put up an awning to serve as a temporary continuation of the roof. One may also take down whatever was temporarily added on Shabbat (SA 315:2; MB ad loc. 38).

Even if no one had actually begun to spread out the awning before Shabbat, but it contains a pull-string that is designed for extending it, this string is considered the beginning of the extension, and thus one may complete the extension of the awning on Shabbat (MB 315:37).

A porch’s sliding roof that is attached with hinges or that slides on a track may be opened and closed on Shabbat. This is because it is not considered an ohel, but rather is comparable to opening and closing a door (Rema 626:3). Similarly, one may open a patio umbrella that is permanently affixed in the yard.

The hinged hood or canopy of a baby carriage or stroller may be opened and closed on Shabbat. Furthermore, since it may be opened, it is considered the beginning of an ohel, and one may add to it as well. Thus, if one wishes to protect more of the carriage by extending the hood using a cloth diaper or a plastic sheet, he may do so (SSK 24:13).

05. Additional Laws Pertaining Ohel

As we have seen, making even a temporary ohel is rabbinically prohibited. Included in this prohibition is placing a wide board or a sheet across vertical supports to protect oneself from the elements. However, when the supports are not permanent, this can be permitted if the ohel is erected in a manner that differs significantly from the normal way of doing it. The Sages forbade putting up a temporary ohel in the usual order – first putting up the walls or supports, and only then putting up the roof. However, if the order is reversed, the Sages permit one to put up a temporary ohel. Thus, if the roof is first held up in the air and then walls or supports are placed underneath it, this would be permitted. Usually a second person is necessary in order to erect a tent in this way (Shabbat 43b; SA 311:6; Bi’ur Ha-Gra ad loc.).

These rules apply to children’s games as well. Children who are of an age where they can understand the laws of Shabbat may not spread blankets over chairs in order to create a tent in which to play, but they may hold the blanket in the air and then place chairs underneath it. Similarly, they may not use interlocking toy bricks (like Lego) to build a house or garage whose inside area is a square tefaĥ or more, but they may hold the roof up and then attach the walls from underneath.

Just as one may not put up a temporary ohel, one may not take one down. Just as one may put up a temporary ohel if he changes the order of construction, so too he may take one down if he changes the order. The walls must be removed first, and only afterward the roof (SSK 24:22).

Even if there is no intention to erect an ohel in order to take shelter under it, nevertheless, if in actuality one makes something in the form of an ohel and the space underneath serves a purpose, it may not be erected in that form. For example, one may not take two barrels of wine and place a third one across the top. Since it is necessary to have airflow between the barrels so that the wine will not get overheated and spoil, this structure is considered a temporary ohel: the two barrels are considered walls, and the barrel atop them is considered a roof. However, the Sages permit doing so if the order is reversed; one person may hold up the top barrel while someone else slips the other two barrels underneath.

One may place a tabletop on legs as long as each leg is less than a tefaĥ wide. In such a case, the legs are not considered meĥitzot, and one may set the legs first and then place the tabletop on top of them. If each of the legs is a tefaĥ wide, they are considered meĥitzot. If one wishes to set up such a table, he must hold the tabletop in the air and then have someone else slip the legs underneath it.[4] In contrast, when opening a folding crib, one may place the board and mattress normally, as there are no walls beneath them and there is no purpose served by the space underneath them.

One may open a baby carriage or stroller, a folding table, a folding chair, a cot, or a playpen on Shabbat because the entire structure is already completed and connected before Shabbat. The only part that is done on Shabbat is opening it (SA 315:5).

One may not cover a very large barrel (whose diameter is close to a meter), as this resembles making an ohel if a tefaĥ of open space remains (Shabbat 139b; SA 315:13). However, if the cover of the barrel has a handle on it, then it is clear that this is simply the cover of a receptacle and not the roof of a tent, and thus one may place it on top of the barrel (SSK ch. 24 n. 72). One may overturn a large pot and use it to cover food and protect it from the sun or insects, because overturning a pot is not considered making an ohel. Similarly, one may overturn a recliner or couch even though space is created underneath it, because overturning furniture is not considered making an ohel (BHL 315:5, s.v. “kisei”).

Many maintain that it is rabbinically forbidden to put on a hat with a hard brim a tefaĥ wide, because doing so is considered making a temporary ohel. This is despite the fact that one may use a hand fan to shield himself from the sun and hold a talit horizontally over one who is called up to the Torah in honor of his marriage. Nevertheless, a hat that remains on one’s head without moving is more similar to a temporary ohel (Shabbat 138b; Rabbeinu Ĥananel; Rambam; SA 301:40). The custom, though, is to be lenient and to allow one to wear a black hat, since it is worn primarily for the sake of honor and not to provide shade. It is also possible that the brims of today’s hats are not considered hard (MB 301:151). Alternatively, perhaps the custom relies on Rashi, who maintains that a hat is never comparable to an ohel; the only concern is that if one’s hat is blown off, people might chase after it and end up carrying it.

The universal custom is to forbid using an umbrella on Shabbat because it resembles an ohel (see BHL 315:8, s.v. “tefaĥ”; SSK 24:15).

[4]. According to Rabbeinu Tam, Rosh, Smak, and Hagahot Maimoniyot, if the meĥitzot (that is, legs that are more than a tefaĥ wide) were set up before Shabbat, it is not forbidden to place the tabletop on them. If the legs were set up on Shabbat, then one may not place the tabletop on them even if the space underneath is not being used. However, according to Rashba, Ran, and Magid Mishneh, even when the legs are narrower than a tefaĥ, if the space underneath is needed then one may not place the tabletop on them. According to Tosafot (as quoted by Rashba) and Tur, two conditions must be met in order for the placement to be prohibited: 1) the meĥitzot must be put into place on Shabbat; and 2) the space underneath must serve a purpose. Since this law is rabbinic, SA 315:3 follows this lenient position. Therefore, if the legs are less than a tefaĥ wide, even if the space underneath it is used, for example, as a place for people to put their feet, one may set the table up in the usual way. Some, however, beautify Shabbat by changing the order of the setup even in this case, as explained in Harĥavot.

06. Permitted and Prohibited Implements

Just as Boneh and Soter apply to building or demolishing a house, the ground, or an ohel, they also apply to building or demolishing an implement.[5] Therefore, one may not insert the handle of a hammer into the hammer head or a broom handle into the broom shaft. A permanent insertion is prohibited by Torah law, while a temporary insertion is forbidden rabbinically. Similarly, it is prohibited by Torah law to put together a bed or chair using nails, screws, or glue, since such attachments are full and permanent. Fixing a chair leg or table leg that has fallen off is also forbidden, as is attaching or removing a rubber chair tip or table tip (a rubber protector that goes underneath a chair leg or table leg).

If there is a possibility that people will forget it is Shabbat and end up fixing the implement, the Sages forbid moving it. For example, if a leg falls off a chair or table, one may not move the item and prop it up on another piece of furniture, because someone might see it and decide to repair it. However, if the implement would be complicated to fix, or if it had already been used in this manner before Shabbat, there is no concern that he will forget and repair it on Shabbat, so it may be moved (SA 313:8; Rema 308:16; MB ad loc. 69; SSK 20:44).

One may use implements on Shabbat whose normal usage involves screwing or unscrewing. Thus, one may screw a lid on a jar, salt shaker, or pressure cooker, put on jewelry whose ends screw together, or look through binoculars that are focused by turning a knob. Since this is the normal way of using these devices, screwing and unscrewing them is not considered a melakha. However, one may not unscrew something if it unusual to do so. For example, one may not unscrew the knob of a pot cover (SHT 313:32; MA states that the prohibition is by Torah law, while Taz maintains that it is rabbinic).

Most poskim allow adjusting the height of a lectern (“shtender”) by loosening a knob and tightening it at the desired height, as this is the normal usage and the lectern remains usable at every stage of the adjustment (Orĥot Shabbat 8:9 citing R. Shlomo Zalman Auerbach and R. Yosef Shalom Elyashiv; Yalkut Yosef 314:2).

One may adjust a baby carriage or stroller with hinges or latches from an upright position to a horizontal one and vice versa. However, if doing so involves removing screws that hold the seat in position and then screwing them back in, it is forbidden because it entails making a strong attachment that is adjusted only infrequently (SSK 28:50).

[5]. Beitza 22a states that “Beit Shammai maintains that Boneh and Soter apply to kelim, while Beit Hillel maintains that Boneh and Soter do not apply to kelim.” The halakha follows Beit Hillel, as Rava rules in Shabbat 122b. However, we find in Shabbat 102b that according to Rav, one may not insert the wooden handle into the metal blade of a scythe as it constitutes Boneh. Tosafot ad loc. (s.v. “hai”) explain that in a case of bona fide assembly, Boneh and Soter apply to implements as well. The statement that Boneh does not apply to implements refers to loose attachments, as I wrote in the main text. This is also the opinion of Smag, Rosh, and Tur. Ramban, Rashba, and Ritva (on Shabbat 102b) maintain that one may not build an implement in its entirety because of Boneh, but adding onto an implement is prohibited because of Makeh Be-fatish. Rashi Shabbat 74b and Yere’im maintain that even creating an implement is prohibited on account of Makeh Be-fatish, not Boneh. The practical significance of this halakhic disagreement is when it comes to Soter. If the prohibition is on account of Makeh Be-fatish, then undoing one’s actions is not prohibited by Torah law, as Soter is defined as undoing an act of Boneh. Therefore, if undoing what was done to an implement is necessary for Shabbat, according to Ramban and those who follow his approach one may do so, while according to Rashi and those who follow his approach it would even be permitted to take the entire implement apart. However, according to Tosafot and Rosh, this would be forbidden even for a Shabbat need. Only when dealing with a low-quality implement (such as a mustekei – a barrel made of an inferior material) would it be permissible to take it apart for a Shabbat need, as explained below in section 11. SA 314:1 rules in accordance with Tosafot and Rosh. However, in 314:7, in the context of asking a non-Jew to break a vessel for a Shabbat need, it is lenient in accordance with Rashi and those who follow him. The justification for this leniency is that two mitigating factors are involved: asking a non-Jew to do melakha on Shabbat (which is only a rabbinic prohibition) and a Shabbat need (for example, if the fruits in the vessel are otherwise inaccessible). See Menuĥat Ahava 3:23:32. Rambam (MT 10:13) follows Tosafot, maintaining that Boneh applies to implements. On the other hand, he permits breaking a barrel to get to the food inside it, even if the barrel is not considered a mustekei (MT 23:2). See Kaf Ha-ĥayim 314:5.

07. Permissible Assembly and Disassembly of Implements

There is a difference between attaching things to a house and attaching things to an implement. One may not add anything to (or remove anything from) a house even if it is attached loosely, since the house is considered permanent. For example, one may not install a window on its hinges or remove it from its hinges. Although it is attached loosely and it is easy to make or break this attachment, it is forbidden because the window is part of the house. Note that if a wardrobe or free-standing closet has a volume of forty se’ah (three cubic amot, or just over ten cubic feet) it has the same status as a house. Thus, one may not connect anything to a large wardrobe, even loosely (Rema 314:1).

In contrast, devices, which are less permanent, may be assembled using temporary attachments that do not require craftsmanship or strength. Therefore, one may assemble and disassemble a portable cot of the type travelers use, which can be assembled and disassembled daily, and which is loosely attached (Shabbat 47a-b; SA 313:6). Similarly, one may remove the door of an implement that is easily assembled and disassembled and that turns easily on its hinges. Technically, one should be permitted to place this door on its hinges as well. However if the hinge is attached to the implement with nails or screws, the Sages forbid it out of concern lest one tighten the attachment and thereby transgress a Torah prohibition. Only if nothing can be tightened, such as if the hinge is part of the implement, may the door then be attached to the implement (Shabbat 122b; SA 308:9).

The general principle here is that if an implement is normally assembled with a firm attachment, the Sages forbid even attaching it loosely. They were concerned that one might forget and attach it firmly, thus transgressing a Torah prohibition. However, if an implement is assembled with temporary and easy attachments, there is no reason to fear that one will attach it firmly and thus transgress a Torah prohibition, and it may be assembled and disassembled. Therefore, one may extend a table by adding a leaf designed for this purpose, and one may remove a leaf as well, since the leaves are clearly temporary. Similarly, the feeding tray on a child’s high chair, which is constantly attached and detached, may be used freely on Shabbat, since the attachment is loose.

Based on this, many maintain that the prohibitions of Boneh and Soter do not apply to building with interlocking toy bricks (like Lego) and the like, since the pieces are attached to each other temporarily and are designed to be disassembled (Tzitz Eliezer 13:31; Yeĥaveh Da’at 2:55; but SSK 16:19 is stringent).

Some Aĥaronim maintain that it is rabbinically forbidden to make paper airplanes or boats or to fold napkins into special shapes because this resembles Boneh (R. Shlomo Zalman Auerbach cited in SSK 11:41; 16:21). Others permit this on the basis that the prohibition of Boneh does not apply to things that are temporary and will soon be disassembled (Rivevot Ephraim 1:223:8 quoting R. Moshe Feinstein). One who is lenient has an opinion to rely on, and one who is stringent is commendable. Children may be lenient even le-khatĥila (see Harĥavot).

08. Fixing Broken Implements

Some items are sturdily assembled initially but loosen over time. If people are used to using these items in their loosened state, it is not prohibited to assemble or disassemble them. As noted, assembling implements loosely is not considered Boneh. Furthermore, since people are used to using them this way, we are not concerned that they will end up fixing them with nails or glue (see Rema 308:16; SA 313:6).

Thus, if a wheel falls off a baby’s crib and people are comfortable using the crib after replacing the wheel loosely, it may be replaced. Similarly, rubber chair tips and table tips may be replaced if they are only loosely attached. This is also the case if the leg of a child’s doll has come off: if the leg is attached to the doll tightly, it may not be snapped back into place, but if it is connected loosely, it may be replaced.

If a temple fell off a pair of glasses, it may not be screwed back into place, since generally it is screwed on tightly. One may not even attach it loosely, because one may forget and tighten it, thus transgressing a Torah prohibition. However, if the screw is lost, there is no longer a concern that anyone will tighten it. Thus, one may reattach the temple using a safety pin, as this is a weak attachment that is permitted for implements (Shulĥan Shlomo 314:11:2).

If a lens fell out of the glasses’ frame and replacing it requires screwing it back in, it may not be replaced at all, even if the screw is left loose. This is because we are concerned that later on one will forget and tighten it. But if there is no screw, but rather the frame has expanded a bit so that the lens sometimes falls out, then the lens may be replaced in the frame. We are not concerned that one will permanently reattach it, as that would require expertise (Menuĥat Ahava 3:23:35; Orĥot Shabbat 8:49-50).

One may not straighten a spoon, knife, or glasses temple on Shabbat by hand, because this is considered Makeh Be-fatish (MA 340:11; MB 509:1, 7; see Harĥavot).

The prohibition of Boneh does not apply to compressing a spring on a toy car so that the car will move forward. One may do so as long as the car does not make noise or light up (see SSK 16:14).

One may inflate an air mattress, air pillow, or rubber ball that had been previously inflated. Since this is permissible, it may be done in the usual fashion, using a manual pump. However, one may not inflate these items for the first time on Shabbat, because many poskim maintain that inflating them for the first time makes them into viable implements for the first time, which is prohibited. One may not blow up a balloon even if it had previously been inflated, lest one tie a knot at the bottom. However, if the balloon is sealed with a valve instead of a knot, and it had previously been inflated, it may be inflated on Shabbat (SSK 15:89; 16:7; 34:24).

09. Cleaning the Floor and Making Repairs

If the floor is dirty, and leaving it in such a state dishonors Shabbat, one may sweep the floor. A yard, though, may not be swept, because one may end up leveling the ground and thus transgressing Boneh (see section 2 above, n. 1).

In contrast, one may not wash the floor, since leaving the floor unwashed does not dishonor Shabbat as leaving it unswept does, and there is concern that one who washed an area with a hard floor will end up washing a dirt floor as well, which would involve leveling the ground and thus transgressing Boneh (SA 337:3; MB ad loc. 3). However, if water spilled on the floor, one may remove the water using a squeegee (SSK 23:7).

If a particular spot on the floor has become especially filthy, for example, if juice spilled on it, one may pour a bit of water on it and then either wipe it away with a squeegee or soak it up with something that would not normally be wrung out (R. Shlomo Zalman Auerbach cited in SSK ch. 23 n. 30; Yalkut Yosef 337:2). If the entire floor is filthy, one who is lenient and pours water on it and wipes it away with a squeegee has an opinion upon which to rely (Or Le-Tziyon 43:8).

If clumps of grass are blocking a drainage pipe, causing water to back up onto the roof and leak into the house, the Sages permit stepping on the clump to break up and remove the blockage. Normally, even fixing something with a shinui is rabbinically prohibited, but in this case, where otherwise a loss will be incurred, the Sages permit (Ketubot 60a; SA 336:9).

Based on this, some prohibit unclogging a sink using a plunger. They maintain that the Sages permit removing blockages only if a shinui is used, but using a plunger to break up a blockage is the normal way to deal with this problem. Thus it is forbidden by Torah law, and even in a time of need one may not be lenient (Yabi’a Omer 5:33; R. Yosef Shalom Elyashiv). In contrast, others permit this, maintaining that a blockage that can be broken up using a plunger is not a total blockage, and thus breaking it up is not considered a true repair. Furthermore, the improvement that is made is not to the pipe itself. Rather, one is simply dislodging the sludge that clogged it (Minĥat Yitzĥak 5:75; R. Shlomo Zalman Auerbach cited in SSK 12:18; Menuĥat Ahava 3:24:29). In practice, in a case of need, it is proper for two people to hold the plunger and unclog the drain together. This way, even according to the stringent opinion, the prohibition would only be rabbinic; and when in doubt about a rabbinic mitzva, the halakha follows the lenient position. (See above 9:3 and n. 1.)

All agree that one may not remove a blockage using professional equipment like a plumber’s snake. It is also forbidden by Torah law to take apart the pipe under the sink in order to empty it of sludge and then reassemble it.

One may remove garbage that accumulates in the sink strainer. It is not necessary to do this with a shinui, because this action does not fix anything; one is simply removing filth (SA 308:34; SSK 12:17; below 22:12).

One may not oil a door’s squeaky hinge or a baby carriage’s wheel, as this is considered a repair (SSK 23:43; 28:53). If pantyhose start to tear (or “run”), one may not put nail polish or soap at the tip of the run to prevent further ripping, because this reinforces the hose (SSK 15:77).

10. Meĥatekh

The melakha of Meĥatekh is instrumental in transforming raw material into houses, implements, clothing, etc. For example, if one wishes to make leather clothing, he must first cut the leather to the right size. If one wishes to build a house, he must cut the stones, metal, and panels to the right size. If one wishes to install a window, he must cut the glass to the right size. The general principle is that one who cuts something to a specific size on Shabbat transgresses the Torah prohibition of Meĥatekh. Similarly, it is forbidden by Torah law to cut off the soft part of feathers in order to make pillows and blankets, since one must cut precisely between the hard and soft sections (Shabbat 74b). This is the distinction between Meĥatekh and Kore’a: the primary purpose of Kore’a is to separate two distinct parts, whereas the primary purpose of Meĥatekh is to cut with precision in order to create something new.

The melakha of Meĥatekh does not apply to foods. Therefore one may cut a cake into equal-sized pieces. Similarly, one may cut grooves into an orange in order to peel it. Pills and suppositories used by sick people are also considered food for this purpose, and may be cut where scored (SSK 33:4).

Items that animals would consume are considered food and thus not subject to Meĥatekh. Therefore, one may use a knife to cut straw or hay to use as a toothpick. However, one may not fashion a toothpick from hard wood. Since it is inedible to animals, cutting it to size constitutes Meĥatekh: if by means of a tool, one violates a Torah prohibition, and if by hand, which is considered a shinui, a rabbinic prohibition (Beitza 33a-b; MT 11:7; SA 322:4; MB 322:13, 18).

One may take fragrant branches of hard wood that were harvested before Shabbat and trim or rub them so that their aroma spreads. One may also break them into smaller pieces so that more people can smell them. Even though the branches are hard and animals would not eat them, one may break them, since the size of the pieces does not matter. One may only do so on condition that they are broken by hand. If he uses a tool, we are concerned that he will forget and fashion a toothpick, thus transgressing Torah law (Beitza, loc. cit.; SA 322:5; MB ad loc. 17-18; Rema 336:8).

11. Opening Cans

One may open cans on Shabbat in order to eat the food inside them. Since cans are disposable and meant for single use, they are not considered true receptacles and are more akin to shells that are broken to get at the nut within.

Similarly, we read in the Mishna: “One may break a barrel in order to eat the dried figs inside it, as long as he does not intend to create a receptacle” (Shabbat 146a). Many explain that this mishna refers to a mustekei, an inferior sort of barrel meant for a single use. Because the barrel was unimportant, it was secondary to the food inside it, just as a nutshell is secondary to the nut inside it. Thus, one may break the barrel in order to eat its figs. They would not break the barrel in a way that scatters the figs; rather they would break off the top, and the figs would remain within for several days, until they were all eaten. The Sages did make one condition: “As long as he does not intend to create a receptacle.” If one makes a neat opening and plans to reuse the barrel to store other things, then he is truly creating a receptacle when he opens it, and is thus transgressing (SA 314:1).

The same applies to cans. One may open them on Shabbat if one plans to eat their contents, even if it will take several days to finish the food. Once the food is finished, the can is thrown out; therefore it is considered unimportant and may be opened on Shabbat. However, one who intends to reuse the can for other items may not open the can on Shabbat, since he is creating an opening and rendering it usable, which amounts to creating a receptacle.

Some are stringent and do not open cans on Shabbat even when they intend to throw them out. Since the can is in fact capable of storing additional items, creating an opening for it essentially makes it into a receptacle (Ĥazon Ish 51:11). However, in practice the halakha follows the lenient position. Since we are dealing with cans and containers that are designed to be disposable, it is not forbidden to open them. Those who wish to be stringent should open cans before Shabbat. If they need to open a can on Shabbat, they should immediately empty it of its contents.[6]

[6]. Along the same lines as the dispensation quoted in the mishna above, a beraita cites R. Shimon b. Gamliel as stating: “One may bring a barrel of wine and chop off the top with a sword” (Shabbat 146a). This is because the person does not intend to make a neat opening. He simply wants to get to the wine. This is the ruling of SA 314:1 and 314:6. However, Rishonim disagree regarding the type of barrel to which the dispensation applies. Tosafot and Rosh understand that the dispensation refers to a mustekei barrel, which broke and was then put back together using tar. In contrast, Ran maintains that even a high-quality barrel may be broken in order to reach the food inside it. This would also seem to be the opinion of Rambam (MT 23:2). SA 314:1 is stringent like Tosafot and Rosh. In any event, even according to the more stringent opinion, today’s cans would not be considered better than the mustekei barrels of the Talmud, which were meant to be used only once. For example, the mustekei barrel that was broken open could not be reused. In order to store dried figs or wine in the barrel, its top would have to be reattached.Ĥazon Ish 51:11 is concerned that a can becomes a receptacle upon being opened. If so, opening it is not breaking it but rather creating a receptacle (kli), because it can now be used repeatedly. However, many maintain that the can was already a kli prior to being opened, as in fact it preserved the food within it (Tehila Le-David 314:12). Opening it thus destroys it, as it can no longer be used. Even if, 60 years ago, many people used cans to store nails and the like, today almost no one does this (Or Le-Tziyon 1:24). Those who are lenient here include R. Shlomo Zalman Auerbach (SSK 9:3 and Shulĥan Shlomo 314:5); Minĥat Yitzĥak 4:82; R. Ovadia Yosef (Halikhot Olam vol. 4, p. 250); and R. Mordechai Eliyahu. However, in order to avoid the problem raised by Ĥazon Ish that one might be creating a receptacle, some suggest puncturing the bottom of a can before opening it. Then, when it is opened, it does not become a receptacle because there is a hole in the bottom (SSK 9:3). On the other hand, many who follow Ĥazon Ish feel that one may not even make this first hole (Minĥat Ish 17:3). Additionally, those who feel one may open a can should not make the hole because it is a destructive act, which is rabbinically forbidden. Moreover, sometimes puncturing the can may cause a violation of Borer. Thus, it is preferable to open a can in the normal way. One who wishes to comply with the stringent opinion as well should open cans before Shabbat, or at least empty them out immediately after opening them.

12. Opening Bags and Wrappers

Many dairy products are sold in plastic containers. One may peel the cover of such a plastic container. Similarly, packages of wafers and chocolate bars may be opened. Since the wrapper is meant to be disposable, it is secondary to the food inside it, just as an orange peel is secondary to the orange and may be removed in order to eat the orange.

One may make a hole in the top of a bag of milk or juice in order to pour out the liquid, open the top of a bag of sugar that is glued shut, and rip open bags of candies or other foods.

Similarly, we find that the Sages permitted cutting open ĥotalot (palm leaves used to protect unripe dates) on Shabbat. They permitted this because these leaves lacked importance, as they were considered entirely secondary to the dates inside them, similar to an orange peel. (Shabbat 146a; Kol Bo; SA 314:8).

Some are stringent and do not open bags or packages if the food will remain inside for a while, as is the case with a bag of sugar. They maintain that one who makes a neat opening is not ruining the bag, but rather is creating a receptacle (Ĥazon Ish 51:10). According to this approach, the only way to open such bags is to tear them apart entirely and transfer their contents to a different container.

In practice the halakha follows the lenient position, because these bags have no importance and are thrown out after the food they contain is finished. Therefore, one may open them in whatever way enables easy removal of their contents, and he may use them until the food inside is used up.[7]

It should also be mentioned that when opening these bags, one should try not to tear any letters. However, if necessary, one may open the bag even if it is clear that doing so will tear letters (as explained below, 18:3).

Similarly, one may open packages that contain items that are necessary for Shabbat, such as tissues and diapers. It is proper to open them more messily than one would during the week. Those who follow the stringent opinion would need to destroy the packaging so that it can no longer hold its original contents. The halakha is in accordance with those who are lenient.[8]

[7]. The dispensation to tear ĥotalot (Shabbat 146a) is not limited, so even if the opening allows the dates to be removed easily, there is no prohibition. Even in the case of a mustekei barrel (Shabbat 146a; Beitza 33b), one may make an opening through which the contents can be removed over the course of a few days, on condition that there is no possibility that it is a neat opening, which would allow the barrel to be used repeatedly. Therefore, the mishna in Shabbat allows making an opening in the top of a barrel even if it is made to pour out wine. Only if the hole is made in the side of the barrel, where it is clear that the opening is meant to be used multiple times, is it forbidden (Shabbat 146a). Indeed, this is the ruling of SA 314:6. The reasoning behind all these permissive rulings is that since we are dealing with packaging that is meant to be used only once, the container is secondary to the food within it. Thus, it is comparable to the peel of a fruit, which may be cut up and removed with no limitations. Even when the package is large and it will take days to finish up what is inside, as is the case with a milk carton or a bag of sugar, there is no prohibition, as the Sages permitted opening a wine barrel or ĥotalot even though they were not immediately emptied out. (This is also implied in m. Kelim 16:5, according to the explanation of Rash.) It is only if a neat hole is made in the package, in order to allow multiple uses after the current contents of the package are finished, that there is a prohibition. In contrast, when dealing with containers of milk, packages of sugar, and the like, it would never dawn on anyone to reuse them, so there is no issue of Boneh or Kore’a when opening them. Those who are stringent maintain that the dispensation to make an opening is limited to something that is not part of the packaging itself but only adheres to it, like the lid of a barrel; but if one makes a neat opening in the package itself to pour the milk or measure out the sugar, it is like making a receptacle. However, the prohibition is only rabbinic, since the opening only serves for the contents’ removal, not their reinsertion (Ĥazon Ish 51:10; see Orĥot Shabbat 12:6). They are also concerned about Kore’a when opening a bag of sugar, since many maintain that tearing is prohibited if it serves a constructive purpose. However, we have already seen that the law pertaining to a package of food is the same as that of ĥotalot, where the prohibition of Kore’a is completely irrelevant. Some of the lenient opinions concede that ideally one should comply with the stringent position and open packages before Shabbat. If it is necessary to open a bag of milk on Shabbat, le-khatĥila it is better to make a smaller opening than one normally would during the week or to tear the plastic with one’s teeth, so that it is clear that one does not mean to make a neat opening. This way, even some of the stringent opinions would concede that it is permissible.

[8]. The law of opening packages of clothing and the like is the same as that of packages of food (R. Shlomo Zalman Auerbach, Shulĥan Shlomo 314:7:6). Just as one may use packages of food until their contents have been finished, so too when opening packages of tissues or diapers he may use the packages until their contents have been finished. Those who are stringent require destroying the packaging entirely (Minĥat Ish 17:22; Orĥot Shabbat 12:23). According to Yalkut Yosef 314 n. 22, one should not rip the wrapping paper off a book or picture, because those who are lenient only permit tearing a package when the item is needed for Shabbat, and that is not the case here. It would seem in practice that one may do so if there is a need. However, MB 340:41 and BHL s.v. “ha-niyar” prohibit opening a letter even if there is a great need. On the other hand, Maharil, MA 519:4, and Taz ad loc. 5 permit it. Since the prohibition is rabbinic and there is a need, one may be lenient.

13. Opening Bottles

Poskim disagree about whether one may open a wine bottle that has a metal screw cap. Some prohibit opening it, maintaining that before the bottle is opened, the cap is simply a cover, but after it is opened and separated from the little metal rim that is left behind on the bottle, it becomes an implement, because it has become a screw cap that aids in opening and closing the bottle (R. Shlomo Zalman Auerbach).

However, most poskim are not concerned about opening such a cap. They maintain that even before it is opened it is already considered a bottle cap. Opening it does not create a new entity. Separating the metal rim from the cap is comparable to cracking open a nutshell in order to eat the nut. Additionally, the one who opens the bottle has no intention of making an implement; he just wants to open the bottle. Even though it happens to be that a screw cap is created, there is no prohibition.

Although one who wishes may be lenient may do so, and there are many who are lenient in practice, le-khatĥila it is preferable to defer to the stringent opinion and open such a bottle before Shabbat. An additional solution is to keep around old bottle caps and then immediately throw out the new cap after opening a bottle on Shabbat. Since in this case there is no intention to use the bottle cap that was opened on Shabbat, even those who are stringent would concede that one may open it.

If no old bottle cap is available and a bottle was not opened before Shabbat, another solution for those who are stringent is to puncture the bottle cap before opening it. This effectively ruins the bottle cap so that after it is opened it is not considered an implement (SSK 9:18). According to those who are lenient, it is preferable to open the cap without puncturing it.

Even most of those who are stringent regarding a metal bottle cap maintain that a plastic cap may be opened, as this is considered a bottle cap even before it is opened. Thus, opening a plastic bottle cap does not make it an implement (SSK 9:21). This is the custom. One may also use a corkscrew to remove a cork on Shabbat.[9]

[9]. The stringent opinion of R. Shlomo Zalman Auerbach regarding the removal of metal bottle caps is quoted in Shulĥan Shlomo (314:9:4-5). It is also recorded in SSK 9:18 and Orĥot Shabbat 12:17. Responsa Devar Yehoshua 2:45 disagrees with R. Shlomo Zalman Auerbach, based on Magid Mishneh 12:2, which explains that as long as one does not intend to create an implement, we do not consider it a psik reisha. Therefore, one may pour a large quantity of cold water into a very hot kettle. Since he does not intend to temper the kettle and thus apply one of the final stages of the metal forging process, it is not prohibited even though in fact he is doing so. MA 318:36, Bi’ur Ha-Gra 314:11, and MB 318:80 follow this position. Here too, one’s intention is to open the bottle, not to produce a bottle cap. R. Shlomo Zalman Auerbach disagrees with this position, maintaining that even though one’s primary intention is to open the bottle, he also wishes to produce a bottle cap. However, many believe that the bottle cap was considered functional even before the bottle is opened, but could not be used in practice because it was attached to the bottle by the metal rim. This is the approach of Tzitz Eliezer 14:45:1, Yeĥaveh Da’at 2:42, and Or Le-Tziyon 2:27:8; R. Mordechai Eliyahu ruled this way as well. If one intends to throw away the bottle cap, R. Shlomo Zalman Auerbach agrees that one may open the bottle (as explained by Devar Yehoshua ad loc.). If one needs the cap, R. Shlomo Zalman Auerbach allows him to puncture it and then open it, because by doing so he renders it less functional as a bottle cap. However, according to those who are lenient, since it is not necessary to puncture the cap, it is questionable whether one may do so. If it is considered an implement even before it is opened, it is rabbinically prohibited to destroy it. If it is comparable to a mustekei, it might be permitted to destroy it (even if it is not necessary). Those who take into account the opinion of R. Auerbach and his followers do so in an attempt to avoid a possible Torah prohibition.According to R. Shlomo Zalman Auerbach, one may remove the ring that remains on a metal or plastic bottle cap, since the cap is already functional without it. Others forbid this on account of Makeh Be-fatish. R. Yosef Shalom Elyashiv maintains that this is forbidden because of Meĥatekh (Orĥot Shabbat 12:19-20). It would seem that even those who prohibit this would agree that the prohibition is rabbinic.

14. Opening Soda Cans and Separating Attached Plastic Containers

Some forbid opening a pop-top can on Shabbat. They are concerned that this action may constitute Boneh, because it creates a neat opening that allows one to drink. They are also concerned that one may be transgressing Meĥatekh, because the tab is pre-scored and produces a very precise opening.

However, many permit this, maintaining that because the can is meant to be disposable, opening the top does not create a receptacle. Rather, it is comparable to breaking a barrel in order to remove the wine inside it. Meĥatekh is also not an issue, because that applies only when material must be cut to an exact size. Since it does not matter where a cut is made on the can, and the only goal is to create an opening for drinking, the can may be opened in the most convenient way possible – by lifting the tab.

One may be lenient if he wishes. If one wishes to be stringent, he should not drink from the opening formed by popping the top, but rather should pour the drink from the can into his cup. This makes it clear that he is not interested in the neat opening of the can. If one wishes to be more stringent, he should be careful to lift the tab only slightly, less than he would on a weekday. This way the act of cutting is not completed, and the opening is not as good as it is usually.[10]

There is another case that is subject to debate. Many dairy products (yogurts, puddings, and the like) come in containers that are loosely connected to each other. May one separate them by applying light pressure to that connection?

Some maintain that breaking the containers apart along score lines that are made for this purpose is a violation of the Torah prohibition of Meĥatekh. They are also concerned that this might be Makeh Be-fatish, since separating the containers makes them usable.

Others are lenient, maintaining that cutting is forbidden only when it is precise, and here the goal is simply to separate the containers from one another. No one cares exactly how precise the cut is. Furthermore, it is not Makeh Be-fatish, since the containers were completely ready for use even beforehand. Separating them simply removes an external impediment.

In practice, one who wishes to be lenient has an opinion to rely upon, and one who chooses to be stringent should be commended. It is proper to separate such containers before Shabbat.[11]

[10]. Orĥot Shabbat 11:43 and 12:5 cite R. Yosef Shalom Elyashiv as forbidding opening a pop-top can in the normal manner and R. Shlomo Zalman Auerbach as permitting this. R. Meir Mazuz and Menuĥat Ahava 3:24:5 permit this on condition that one pours the drink into the cup. This approach is also recorded in Eshmera Shabbat 1:1:17. Or Le-Tziyon 2:27:6 permits this on condition that the pop top is not opened entirely, so that the can will not be easily usable. Accordingly, even those who are stringent would concede that a complete melakha was not performed. Yalkut Yosef 314:23 states in the name of R. Ovadia Yosef that technically one may open a pop top, but it is proper to be stringent and not open it entirely.

[11]. Included among the permissive poskim are: R. Shlomo Zalman Auerbach (Shulĥan Shlomo 314:13:3); Or Le-Tziyon 2:27, n. 7; Halikhot Olam vol. 4, p. 254; and Binyan Shabbat 11:3. Included among the stringent poskim are: R. Yosef Shalom Elyashiv (quoted in Orĥot Shabbat ch. 12 n. 22); Ĥut Shani vol. 1, pp. 128-129; R. Mordechai Eliyahu; and Menuĥat Ahava 3:16:14. Even though some state that this is a Torah prohibition, it seems that Rambam (MT Laws of Yom Tov 4:8) maintains that if there is a prohibition at all, it is only rabbinic. Therefore, I wrote in the main text that one who wishes to be lenient has an opinion to rely upon.

There is a debate about tearing open small sugar packets that are often perforated to facilitate tearing them. According to R. Shlomo Zalman Auerbach, one may tear along the dotted lines, because no one cares exactly where the cut is; the point of the perforation is to make it easier to tear open. R. Yosef Shalom Elyashiv, however, maintains that the prohibition of Meĥatekh applies because one is cutting precisely. Therefore, the packet must be torn at a different place (Orĥot Shabbat 11:41).