This section is from the book "A Treatise On Architecture And Building Construction Vol3: Stair Building, Ornamental Ironwork, Roofing, Sheet-Metal Work, Electric-Light Wiring And Bellwork", by The Colliery Engineer Co.. Also available from Amazon: A Treatise On Architecture And Building Construction.
9. The names of different roofs are determined: (1) by their style; (2) by their outline; and (3) by their angle of inclination, or pitch.
In Fig. 10, at (a), is shown a pent, shed, or lean-to roof; at (b), a gable roof; at (c), a hip roof; and at (d), a curb, or cambrel roof.
In Fig. 11, at (a), is shown a Mansard roof with deck, or flat, top; at (b), an ogee roof; at (c), a semicircular, or barrel, roof; and at (d), a hip-and-valley roof.
In Fig. 12, at (a), is shown a dormer-window, with cheeks, or flanks; at (b), an eyebrow window; at (c), a squint with cheeks, or flanks; and at (d), a louvre ventilator.
The pitches are regulated by a recognized standard of the style to which they belong. Thus, at (a), Fig. 13, is seen the pitch, generally found in Grecian design; i. e., inclined from 12° to 16°; at (b), the inclination is from 23° to 24°, which was the rule in Roman design; at (c), is shown the Gothic, or equilateral, pitch; and at (d), the Elizabethan, or knife-edge, pitch.
10. A dome, properly speaking, is a spherical form of roof; the term, however, is now applied to various forms having a circular base; thus, in Fig. 14, at (a), is a surmounted dome; at (b), a semicircular dome; at (c), an ellipsoidal dome; at (d), a segmental dome; and at (e), a bell dome. There are many other varieties, known as Turkish, Saracenic, Russian, etc.