Minecraft wiki entry for Roof_types, associated text: A skillion roof is a roof surface which slopes in a single direction. It may continue the slope of an existing roof, or be separate. A skillion roof may sometimes be called a shed roof or lean-to. This image of a skillion roof shows a 1 in 1 pitch on the right hand side and a 2 in 1 pitch on the left hand side, allowing the roof to extend out over the porch without dropping to ground level.