Minecraft wiki entry for Roof_construction_guidelines, associated text: Note in the two 'roof pitch' diagrams how the width of the building significantly affects the look of the steepest roof. When using steeper roofs, or if you want a central 'feature' that is an odd number of blocks wide (such as a door) make the entire building an odd number of blocks wide. That way the roof will come to a point exactly over the central feature. If the center of your building is to have a double door or some other feature with an even width, then the building width should usually be even too.