Any roof over a shed is a shed roof, right? Well, yes, but there are shed roofs and there is a style known as the shed roof. Most small storage sheds have gable roofs, typically low-angled, with a center peak and slopes to the walls on both sides. But the roof style called a shed roof slopes only one way. It is sometimes called a lean-to roof because it often used on that style shed.
Decks, Patios, Carports
A shed roof may not be over a shed. This type of roof is often used over decks, patios and carports. It frequently has a very low slope and may appear almost flat. These generally are attached to the wall of a house or other building and fastened to a ledger, a horizontal board which serves as a ledge or support for one end of the roof, with posts to support the outer end.
Shed roofs also are popular on dormers, vertical extensions built on a gable or hip style roof. These may be fairly tall structures, often high enough to frame an upstairs room, and the shed style is popular because it offers a lot of space and is easy to build on a conventional pitched roof. These shed roofs are attached to interior framing with an exterior wall to support the outer edge.
Another common use for a shed roof is on a home addition, such as a utility room or game room. The shed style is ideal for this purpose because it can cover almost any size of addition and is easy to build and attach to the existing house. Since you're building a new wall, you can easily adapt its height to form any desired slope from the main roof.
You can, of course, use a shed roof on a shed. In this application, one shed wall is built taller than its opposite wall, typically to form a slope from the front of the shed to the back. Shed roofs on sheds are likely to have steeper pitches, but usually not more than a 4/12 or 5/12, which indicates a rise of 4 or 5 inches per linear foot. Sheds with this style often have open fronts with large overhangs and are used to house tractors and other machinery.