Rashi: Refer to 41:15:5:1.

Radak: I explained Chalonim ha'Atumos above (40:16; they were narrow on the inside and wide on the outside). The Atikim (cells and chambers) were on three sides (west, north and south).

Vilna Gaon: All three of these [had windows and Sipim].

Rashi citing Targum Yonasan: A cedar plank opposite the doorposts of the opening. He covered the thickness of [the sides of] the opening with wood.

Vilna Gaon: The entire Bayis was covered with gold. There was wood under the gold, so they would be able to cover it well (gold does not stick to stone). The wood was big, wide pieces like the size of the wall. However, on the Sipim they were Sechif (thin), like the width of the Saf.

Malbim: The walls were covered with cells and thick wooden planks. However, they could not cover the Sipim and Chalonim ha'Atumos with thick planks, for there the building recesses and juts out; it is [in different places] square, round and triangular. Also the Atikim were built on round stone pillars. Thick planks cannot cover them! Rather, they were covered with thin woods, like [thin] branches. It was only where they wanted to cover with gold; in between, the rocks were seen.

Rashi: He covered both sides of the opening.

Rashi: A wall of cedar planks was made opposite the wall; it reached from the ground until the windows. It covered the windows from the inside ? "v'Chalonim Atumos El ha'Ta'im" (40:16). This was inside, for the entire Bayis was covered with gold, and one cannot stick gold to rocks ¹ . Malbim ? they did so also in Bayis Rishon ² .

Malbim: From the ground until the windows, thick planks covered the wall.

Radak: The windows were covered above.

Vilna Gaon: Also the windows were covered with wood.

Malbim: Also between the windows, thick planks covered there.