Reply To: Why is Lavud Part of the HL"M of M'chitzin?

He asks why the Gemara needs to say (to answer for R’ Meir) that the Hilch’sa of m’chitzin is for gud, lavud and dofen akumah, when it could have said it’s for the third wall.

He answers that according to the Gemara on 7a, the third wall is a wide tefach, placed within three tefachim of the perpendicular wall (lavud), and that this is in fact the intent of the Gemara’s reference to the HL”M referring to lavud.

He then says that this answers a difficult Ramba’m (Shabbos, 16-11), who days that lavud is included in the category of shiurim, which is not what our Gemara says. The Gemara over here is referring to a specific application of lavud, the third wall. The general lavud, though, is in fact not part of m’chitzin, rather, shiurin.