The answer to whether mobs can spawn on slabs depends specifically on the type of slab being used.
Based on the provided reference, areas covered in bottom slabs are unable to spawn mobs. This holds true regardless of the light level in the area.
However, the situation is different for other block types that might appear similar or share properties with slabs. The reference explicitly states that double slabs, top slabs, and upside-down stairs are still spawnable.
Understanding Mob Spawning Surfaces
In Minecraft, mobs typically require a solid, full block surface to spawn on, often coupled with a sufficiently low light level (though some mobs have different requirements or bypass light levels). Slabs, stairs, and other partial blocks behave differently.
- Bottom Slabs: These occupy the lower half of a block space. Because they are considered "partial" blocks in this specific way, they prevent mob spawning on their surface. This makes them a popular choice for creating safe, non-spawnable floors.
- Top Slabs: These occupy the upper half of a block space. The reference confirms these are spawnable surfaces.
- Double Slabs: Created by placing two slabs in the same block space (either two of the same type or different types), these form a full block. As expected from a full block, they are spawnable.
- Upside-Down Stairs: Stairs, whether placed right-side up or upside-down, are also considered spawnable surfaces according to the reference.
Other partial blocks also have specific spawning behaviors. The reference mentions that dirt path and farmland are partial blocks (15/16th of a block in height) and cannot be spawned upon.
Summary of Spawnability
Here's a quick overview of whether common block types mentioned can host mob spawns:
| Block Type | Can Mobs Spawn? | Notes |
|---|---|---|
| Bottom Slabs | No | Prevents spawning regardless of light. |
| Top Slabs | Yes | Spawnable surface. |
| Double Slabs | Yes | Acts like a full block for spawning. |
| Upside-Down Stairs | Yes | Spawnable surface. |
| Dirt Path | No | Partial block, prevents spawning. |
| Farmland | No | Partial block, prevents spawning. |
| Full Solid Blocks | Yes | Spawnable surface (light level dependent). |
Utilizing bottom slabs or dirt paths/farmland for flooring is an effective way to create areas where hostile mobs cannot spawn, enhancing safety around your builds.
