Minecraft: Which Blocks Don't Iron Golems Spawn On?

So
4

I built an iron farm in the air in Minecraft 1.16.1 where iron golems can spawn and then fall down, where they then die from lava. I want to build a building around the farm to make it look better. However, if I build blocks next to the farm, golems can also spawn there, which in turn affects the efficiency of the farm. What blocks or other options can I use to prevent golems from spawning outside the spawn area? And in what radius can they actually spawn? Would be very grateful for help.

Po

On glass or lower steps.

The iron golem https://minecraft-de.gamepedia.com/...s_Spawning in a 16 × 6 × 16 block area at a meeting point, which is marked by a bed or a bell.

So
1

OK thank you. So do they spawn in a square area that is 16x16 blocks and goes 6 blocks up and down? Or did I get this wrong?

Po

Yes

Fl

On leaf too i guess?