What is "Ulam ha'Bayis"?
Rashi: The Ulam of the Heichal.
What is "El Ulam"?
Rashi: This is like Eil 1 (with a Yud) Ulam - the thickness of the sides of the opening. Also in Bayis Sheni it was five thick - 'the wall of the Ulam was five Amos thick, and the Ulam was 11 wide' (Midos 4:7).
Vilna Gaon: An Eil that stood by the Ulam. It stuck out five Amos towards Ezras Yisrael.
Above (9), Rashi said that Eilim are Mezuzos, like round trees made from hewn rocks.
Here it says "v'Rochav ha'Sha'ar Shalosh Amos mi'Po v'Shalosh Amos mi'Po." The wall of the Ulam was five Amos thick, and the Ulam was 11 wide' (Midos 4:7)!
Rashi: The only was I know to resolve this is to say that "Shalosh Amos mi'Po..." means that the width of Kisfos ha'Pesach seal three Amos of the opening on each side (north and south).
Hagahah in Rashi: I saw in other Perushim "Shalosh Amos mi'Po..." is the thickness of the northern Ayil into the interior of the opening in the west.
Radak: The verse means that the width of the Ulam was the amount so that a flank of three Amos remained in the north and south. I.e. the Ulam was 14 wide; with three on each side it was 20, like the coming verse says.
Vilna Gaon: The gate was in the western wall of Ezras Yisrael; it was three thick.
Malbim: "Rochav ha'Sha'ar" is the door, which seals the opening. The Ulam did not have a gate. Its opening was 14 wide. In Bayis Sheni, the Ulam was totally open; here, three Amos on each side were sealed, so they are called Sha'ar, for via this, the opening is called a Sha'ar.
