Molding (decorative)

A "sprung" moulding has upper and lower edges that bevel towards its rear, allowing mounting between two non-parallel planes (such as a wall and a ceiling), with an open space behind.

mouldings have been made of extruded polyvinyl chloride (PVC) and expanded polystyrene (EPS) as a core with a cement-based protective coating.

At their simplest, mouldings hide and help weather seal natural joints produced in the framing process of building a structure.

Placing an ovolo directly above a cavetto forms a smooth s-shaped curve with vertical ends that is called an ogee or cyma reversa moulding.

Necessary to the spread of Classical architecture was the circulation of pattern books, which provided reproducible copies and diagrammatic plans for architects and builders.

[citation needed] However, the study of formalized pattern languages, including mouldings, has since been revived through online resources and the popularity of new classical architecture in the early 21st century.

[citation needed] The middle ages are characterized as a period of decline and erosion in the formal knowledge of Classical architectural principles.