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-patish (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-patish. 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-patish (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.
