A good roof is essential for a good shed. But there are several choices of roof style and materials. The most common styles are gable, saltbox, gambrel, shed and flat. A gable roof slopes on two sides. A saltbox also has two slopes but of different widths. Gambrel roofs have two slopes on each side, the traditional "barn" type. A shed roof has a single slope. A flat roof has almost no slope.
Shingle, Panel or Membrane
The basic options in shed roofing are shingle, corrugated panel or some type of membrane. Shingles may be composite or asphalt material, generally called three-tab shingles, including individual wood shingles or shakes. Corrugated panels come in vinyl, aluminum or galvanized steel, with several color options. Membranes are rubber-type materials usually used only on flat or very low-slope roofs.
Panels Are Easiest
Composite or asphalt shingle roofs require oriented strand board (OSB) sheathing and a felt or asphaltic underlayment. Individual wood shingles or shakes must be installed individually over wood sheathing strips and must be properly overlapped to be weatherproof. Corrugated panels are easiest to install -- and least expensive -- but may not match the décor of the house and landscape. Panel are easiest because they install in large sections and don't require OSB or other underlayment. This saves in both time and material. Panels are fastened to roof joists, while shingle roofs are nailed over OSB sheathing.
Match Material to Design
Roof design will affect the choice of roofing material. Gable and saltbox styles work with any type of roofing except membranes. Flat roofs require a membrane, usually ethylene propylene diene terpolymer (EPDM), which is glued to an OSB underlayment. Some membrane styles are available in panels but are harder to find and more expensive. Gambrel roofs do best with shingles. Shed or low-slope roofs do well with corrugated panels but also can handle composite shingles.
Locale Is Influence
The locale and use of the shed influence the choice of roofing material. Corrugated metal works well in areas with heavy snow and ice, because the slick metal surface sheds those elements better than rougher shingles. Wood shingles and shakes are most subject to damage from strong winds. Composite shingles would be the choice for a shed which needs warmth; metal tends to be colder. Vinyl panels, especially clear or light-colored, afford the most internal light.
Consider maintenance in choosing shed roofing. Corrugated metal is almost maintenance-free but is subject to denting and bending from falling objects, such as tree limbs or large hail. Composite shingles also are very low maintenance and resist small falling objects like hail well. Individual wood shingles or shakes are most subject to damage but individual ones can be replaced fairly easily. A properly installed EPDM roof is maintenance-free but works only on flat or very low slope roofs