Minecraft wiki entry for Roof_construction_guidelines, associated text: As a real-world rule of thumb, the more precipitation an area receives, the steeper the pitch of roofs in that region. In Minecraft it is easy to get a roof pitch with an angle of 63.4°, 45° or 22.5° – just use double blocks for 63.4°, steps for 45° and alternate upper and lower slabs for 22.5°.