The Pediment
The pediment in its original and orthodox employment was a gable conforming to the pitch of the roof. It is framed with mouldings, and the enclosed space is technically known as the tympanum.
No. 180. Cornice where order is not employed.
The use made of the pediment by the architects of the Renaissance was not always justified in the strictest sense. It was often used to vary the sky line, and to form door and window heads. Although the latter use can be to some extent justified in exterior work, a similar employment in interiors may be open to question.
The sloping lines of the pediment are not always straight, sometimes they are in the form of a curve composed of a segment of a circle. The triangular and curved forms are often used alternately in a row of windows with good effect.
The lines of the pediment mouldings are not always continuous; sometimes the sloping or the horizontal lines or both are broken. This is a treatment that cannot readily be justified as the pediment is a feature that implies shelter.
Sometimes ogee curves take the place of the straight sloping lines, and these terminate towards the centre, with scroll ends, leaving an interval between them.
DETAIL OF PEDIMENT
No. 181.
The mouldings of the pediment are the same as those of the cornice, the crowning moulding of which is carried round and omitted in the horizontal course forming the base of the pediment.
Beneath the cyma the mouldings of the cornice are repeated in their proper order, detailing at the lower angles on the top of the horizontal cornice, which terminates with the fillet above the facia.
When dentils and modillions are introduced in the cornice they are invariably repeated in the mouldings of the pediment.
The tympanum or face of the pediment should be in vertical alignment with the face of the frieze. When this space is small it is best left plain, but on a large scale the tympanum affords a very suitable position in which to place sculpture.
The height of the pediment varies according to the width. Thus where the base is short, as in door and window heads, it will be comparatively higher than when used in a façade. The height may vary from a fourth to a fifth of the width of the base.