Trapdoor

The Trapdoor (Also known as Hatch) is a block used as a horizontal door. The original version of this feature was a mod posted on the Minecraft Forums by Djoslin.

They are placed over a single-block hole (but can be placed over a solid block as well) with a solid block directly adjacent. When activated, they will then open by flipping upwards toward the adjacent block. If that block is destroyed, the hatch is as well. Due to this restriction it is currently not possible to create a flat floor with a hatch opening downwards.

When placed outside, rainfall, water and snowfall do not pass through a hatch, but light is let in through the four gaps on its surface.

Usage
As with Doors, Hatches can be controlled with Redstone circuitry. A charge will cause the hatch to change its state, from either on or off, depending on its starting state.

See Tutorials/Trapdoor Uses for Tutorials/Examples.

Bugs

 * Hatches seem to break faster using a pickaxe instead of an axe, like wooden slabs.
 * Hatches may not be placed next to double half blocks.
 * Hatches block movement when approaching from another block on the same level and the hatch has a block exactly 2 spaces above it, but it does not block movement in the same case if approaching from another hatch. This allows one way drawbridges.
 * If there is a ladder beneath a hatch, you can climb down, even if the hatch is closed.
 * If you save the game on a trap door and then join back it puts you in the nearest block.
 * On a Multiplayer server, if you break the hatch with a diamond pickaxe, no matter how many uses it has, it will break instantly.
 * If you break the hatch with an Iron pickaxe, it will not count as a use.

Trivia

 * Sand and Gravel, if dropped onto a hatch will break into items (similar to how sand or gravel falling on a torch will do the same).
 * Liquids (water and lava) cannot fall through a single hole hatch. The hatch counts as a block and can't have something else in it, even in its open state.  Hatches will stop the block above it whether it's open or closed.
 * Hatches will not prevent you from accessing the contents of a chest if the hatch is in the closed state directly above it. This means that they are just like any other Door and allow you to interact with objects on the other side even if the hatch is closed.
 * If you put a trapdoor on a lava block, the lava will disappear and the trapdoor will not be burned. This allows the creation of paths.