Rashi on I Kings
The twenty amohs at the end of the Beis Hamikdosh. The twenty [amohs] which were at the end of the Sanctuary and beyond, and the twenty [amohs] which were at the end of the building, they are the house containing the Ark cover (i.e., the Holy of Holies).
Rashi on I Kings
To the ceiling. He made the walls of cedar until the ceiling to cover the walls of stone in order to coat it with gold.