3,828. The Pavement of the Azarah

Hilchos Beis HaBechirah 1:9

The Temple must not be built with any wood sticking out, just stone, brick and mortar. Similarly, we may not make wooden porticos anywhere in the Azarah; they were all of stone or brick.

Hilchos Beis HaBechirah 1:10

The whole Azarah was paved with luxurious stone. If a stone was uprooted, even if it remained in its place, it becomes unfit since it was damaged. It is prohibited for a kohein to stand on such a stone during the service until it is fixed into the ground again.