I produced this drawing to illustrate my frustration with trying to design affordable buildings in the classical style using off the shelf moldings.
The molding profile, 1-A, drawn in the upper left hand corner is a crown molding that has a 2-1/2 inch projection and a 3 inch drop. (I don’t know what the diagonal facial dimension is, nor do I care. A number of millwork catalogues provide a facial dimension which is useless to an architect trying to work the molding to a vertical wall surface and a horizontal ceiling surface.) It consists of a large cyma recta above a smaller cavetto separated by a fillet. It is a profile that could be easily found at any Lowes, Home Depot or local lumber supply shop.
Immediately to the right is a cavetto molding profile, 1-B, that matches the same cavetto on the crown. This profile is necessary for the lower cornice that sits below the tympanum of a pediment. The cyma recta, which originally served as a gutter for drainage, is carried up across the pediment’s top raking cornice.
Adjacent to profiles 1-A and 1-B are a series of partial pediment drawings at various pitches, such as 8:12 (8 inches of rise per 12 inches of run), 7-1/2:12, 6:12, etc. Each partial cornice has a raking profile that would match up perfectly to the standard 2-1/2 inch x 3 inch crown molding, and are labeled with suffix “A” (2-A, 3-A, 4-A, etc.) In addition, there is a broken pediment return profile that would allow for the proper return of the raking crown molding. These are labeled with the suffix “B.” The raking crown moldings have the same 2-1/2 inch overall projection, and the same cavetto profile as the straight crown molding 1-A, except that the height of the cyma recta varies depending on the pediment pitch. The broken pediment return moldings also have a 2-1/2 inch projection, except that the projection is measured on a horizontal line extending from vertical lines from the far ends. The cyma recta and cavetto profiles are contorted in various degrees to suite the desired pediment pitch.
Wouldn’t it be great to design a broken pediment with a pitch of 6-1/2:12 (6-1/2 inches of rise per 12 inches of run), using 2-1/2 inch x 3 inch crown, and selecting the correct profile for the raking crown and broken pediment return would be a matter of selecting 5-A and 5-B out of a catalogue?