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1950-51 Theatre Catalog, 9th Edition, Page 134 (114)

1950-51 Theatre Catalog, 9th Edition
1950-51 Theatre Catalog
1950-51 Theatre Catalog, 9th Edition, Page 134
Page 134

1950-51 Theatre Catalog, 9th Edition, Page 134

HANDSOME GEOMETRIC DESIGN OF TERRAZO in lobby floor of Miracle, Coral Gables, Fla.. is matched by specially designed inlaid foyer carpet. Note guard rail passing through exact center of figure.

the amounts required to produce the desired color and shade. This can best be done by making test samples, allowing them to dry.

S'l'ained Floor Finish

Attractively colored fioors are secured with the use of certain inorganic chemicals. These are applied to the hardened floor and react with the cement to form new compounds in the concrete to produce the color. Several applications are often necessary before the desired effects

are attained. A mottled or multi-tone effect is generally produced, depending somewhat on the amount of troweling done in finishing. A number of manufacturers can supply the materials used.

Painted Finish

Concrete floor finish may be painted to attain any color effect. Oil paints, rubberbase paints, and synthetic resin paints are available for this purpose. It should be realized that any traffic causes a certain amount of wear, and in aisles and

COLORED STRIPS INLAID IN THE TERRAZZO FLOOR givo the lobby of the Flower, Takomu Park. Md.. a

look of attractive spaciousness and also serve

to direct entering patrons on into the foyer.

other places where foot trafiic is heavy, touching up at intervals may be necessary and an occasional complete repainting required to keep a good appearance.

Concrete should be clean and thoroughly dry when it is to be painted. The recommended procedure in the past has been to allow several months after construction for curing and drying and then to neutralize the surface by mopping it with a solution containing 2 to 3 lb. of zinc sulphate per gallon of water. After allowing 48 hours for this solution to react with the concrete and to dry, the surface is cleaned with water to remove all crystals. It is then allowed to dry thoroughly before applying the paint.

Recent laboratory tests indicate that an even better procedure is to allow the concrete to dry for several weeks after the curing period; then apply generously a solution of 3 oz. zinc chloride and 5 oz. of ortho-phosphoric acid (85 per cent phosphoric acid) per gal. of water. After drying 24 to 48 hours, any dust on the surface should be brushed off, but the surface should not be rewetted before applying the paint. While the laboratory tests gave excellent results with this treatment, actual field applications have been very limited up to the present time.

Three coats of paint are recommended. The first coat should be very thin-about equal parts of thinner and paint give about the proper consistency. Some thinner may be used for the second coat, and the third coat may be applied as it comes from the can.

Scoring and Division Ships

Concrete floors may be marked off into conventional patterns by the use of an ordinary grooving tool on the fresh concrete or with a power-driven carborundum disk cutting appliance on the hardened concrete. An objection to grooves is the difficulty of keeping them clean. When the fioor is mopped the dirt is deposited in the grooves.

Another method of marking off the fioor surface is with metal strips like those used for terrazzo. These have the advantage of eliminating open scoring joints. Shrinkage of the surface tends to localize along the strips, thus preventing surface cracking. The strips are available in brass, nickel silver, zinc, and plastic in 12 to 18 gage and from 1" to 1%" wide. For joints more than 1A3" wide, strips of the "heavy top" type are used. Division strips are used both in single color fioors and in floors having two or more colors. In general, they should be placed not more than 4' apart to be effective. In floors to be finished by troweling and not to be ground, care must be exercised to set the strips at the exact finished level.


Where concrete floors are to be covered with linoleum, composition tile, prefinished wood tile or planking, carpeting or similar materials, it is not necessary to provide a heavy-duty wear< ing surface on the concrete. The dustcoat method of finishing may then be used.

The structural slab is struck off reasonably true at the required floor level and excess water or laitance removed. A mixture of dry materials consisting

1950-51 Theatre Catalog, 9th Edition, Page 134