Chapter XXIII

, and the two examples of ornamental column form work given here from recent work indicate the task before the builder.

[Illustration: Fig. 190.--Form for Molding Fluted Cylindrical Column.]

The form shown by Fig. 190 was used for molding in place fluted columns used in a court house constructed at Mineola, N. Y. The lagging in the form of staves forms a 24-sided polygon and is held in position by hoops and yokes. The molds for the flutes were formed by inserting screws from the outside so as to penetrate the staves and molding half-round ribs of plaster of Paris over them by means of the simple device shown. To dismantle the form the screws were removed and the lagging taken down leaving the plaster of Paris in place as a protection to the thin edges until the final finishing of the building.

The methods illustrated by Fig. 191 were employed in molding columns in place for a church at Oak Park, Ill. The bottom portions of these columns were plain square sections molded in place in square molds. The top portions were heavily paneled. The four corner segments were cast in glue molds backed by wood with wires embedded as shown. After becoming hard they were set on end on the plain column and tied and braced as shown. The side openings were then closed by wooden forms and the interior space was filled with concrete. The surface facing for these columns was bird's-eye gravel and cement, with very little sand, mixed very dry and placed and tamped with the coarse concrete backing.

[Illustration: Fig. 191.--Form for Ornamental Column for Church at Oak Park, Ill.]

~SLAB AND GIRDER FORMS.~--Slab and girder construction for roofs and floors is of three kinds: (1) Concrete slab and steel beam construction in place; (2) concrete slab and girder construction in place (3) separately molded slab and beam construction. The third method of construction is distinct from the others in respect to form work as well as other details and is considered separately in