Responsa על שבת 62:12

First, it is temporary binyan. The meaning of temporary binyan is that it is made, from the outset, to be built and demolished and rebuilt and re-demolished at all times, just as the Tabernacle was built. There is a disagreement among Amoraim: according to the one who maintains that since they camped at God’s word the binyan was considered permanent, we may thus return to the principle that temporary binyan is not binyan. Since we find that the our Talmud [Bavli] states anonymously in the chapter “Ba-meh Madlikin” (Shabbat 31b), in the discussion of one who makes charcoal, in a passage about one who demolishes in order to build at the same location, that since Scripture states that they camped according to God’s word, it is considered an established place, and this is not rejected, we may derive from here that this is the ruling. This is further implicit in Tosafot on Shabbat 94a, s.v. “R. Shimon poter.” Since the halakha is that a temporary binyan does not constitute a binyan, and a parasol, of course, is constructed temporarily. See also Mo’ed Katan 9a, which offers a contrived answer as to why they were concerned [about the fact that they had participated in the construction of the Temple on Yom Kippur] and does not answer that one might distinguish between the construction of the Temple, which does not even supersede the holidays, whereas the “Days of Training” (“yemei ha-mili’im”) [for the construction of the Tabernacle] even supersedes Shabbat, for they erected and dismantled it every day. Perforce, then, building and dismantling it temporarily, every day, was a temporary construction, like a parasol, and is dissimilar to the construction of the Tabernacle at a place of encampment—“by God’s word they encamped.”