This is in contrast to a dual- or multiple-pitched roof.
A single-pitched roof can be a smaller addition to an existing roof, known in some areas as a lean-to roof, and a "outshot", "catslide", or skillion roof in others.
Some Saltbox homes were expanded by the addition of such a roof, often at a shallower pitch than the original roof.
Single-pitched roofs are used beneath clerestory windows.
One or more single-pitched roofs can be used for aesthetic consideration(s).