Let’s say that you are building your base. You built a nice house (that you’ll improve later), planted your crops, you are breeding some animals, maybe you even built a Lava farm.
To avoid having a creeper ruining your hard work you put Torches and other light sources all around the area. If you did your homework you even followed the right Torch spacing so now you are sure that nowhere in your base it is dark enough to let hostile mobs spawn.
But what about the stairs? Surely you also mined your way to the caves underground.
In this article we’ll see if mobs can spawn on stairs and we’ll clarify some misconceptions about hostile mobs spawning on non-full blocks.
Can hostile mobs spawn on Stairs blocks?
Hostile mobs can spawn on every possible non-transparent solid block if their “feet” are in a full air block whose light level is 7 or less. The key to understand if they can spawn on stairs is the “full air block” part.
In the screenshots above we have a normal stairs block on top and on the bottom we have one which is upside down. A mob could spawn on top of the upside down one, because its feet would be in a full air block (which is the one above the stairs block).
But no mob could spawn on the stairs on the left, because its feet would need to spawn in an half air block (half stairs half air), which can’t happen.
Note: if you’re thinking that maybe they could just spawn with their feet in the full air block on top of the half air block, that doesn’t happen either: mobs need to spawn with their feet standing on a solid block, they can’t spawn mid air.
Can hostile mobs spawn on Slabs blocks?
What we just said is also true for slabs. On the top there is a slab that covers the top part of the block and mobs can spawn on top of that without any problem. In the picture on the bottom there is a slab that covers the bottom part of the block and no mob can spawn on that.
Tip: if you want to have a very large and dark mobs-proof area, you just need to cover it in half slabs (that cover the bottom part of their respective blocks).
If you want to know more about other mobs-free blocks (like Magma for example), you can check the video below.
So that’s all you need to know about stairs. These blocks are safe and mobs-free even in complete darkness, so you don’t have to worry about their light level at all. So thank you very much for reading the article this far and I hope I’ll see you again around here. See you and take care!