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1950-51 Theatre Catalog, 9th Edition, Page 133 (113)

1950-51 Theatre Catalog, 9th Edition
1950-51 Theatre Catalog
1950-51 Theatre Catalog, 9th Edition, Page 133
Page 133

1950-51 Theatre Catalog, 9th Edition, Page 133

mulations of building debris until the completion of the structure. To remove accumulated dirt, the surface should be well swept with a stiff broom and thoroughly scrubbed with white soapsuds. A scrubbing machine fitted with wire brushes or pads of hire steel wool is very effective. The suds and dirt should be mapped up and the surface hushed with clean warm water and again mopped.


In lobbies, foyers, and smoking lounges where fioors are particularly subject to lines of tramc, wet feet, spilled soft drinks, dropped candy and popcorn, and sparks from cigarettes, decorative concrete doors are a Wise choice. Since the floors in aforementioned areas of the theatre are far more exposed to the eyes of patrons than that of the auditorium, they must be attractive as well as safe and durable. A good decorative concrete floor will combine the wearing features of the ordinary type with the added quality of eye appeal.


Terrazzo fioor finishes offer unlimited possibilities for decorative effects in concrete, thus combining beauty and durability. In large areas of plain color or in patterns of many colors, they are widely used in theatre floors subject to heavy trafiic and abuse.

Plain terrazzo provides attractive, long-wearing fioors at low cost. More decorative effects are produced by introduction of pattern and by increasing the number of colors. The original beauty of terrazzo is retained with a minimum of upkeep, and terrazzo surfaces are easily kept clean and sanitary. Terrazzo may be laid in individualized patterns, or in colors to harmonize with the color and decorative scheme of the theatre interior.

Terrazzo is produced by laying mixtures of concrete containing marble chips or other aggregates of the desired colors. Additional aggregate is rolled into the fresh concrete when necessary so that 70 to 85 per cent of the finished fioor area will consist of aggregate. Coloring pigments may be added to produce a matrix of almost any shade and color desired. White portland cement should be used where clarity of color is important. After the concrete mixtures have hardened for several days, the surface is ground and highly polished.

Brass strips or dividing strips of other suitable material are used to separate the colors for the desired pattern. They also prevent shrinkage cracks which are particularly objectionable in decorative iioors. The terrazzo course may be bonded to the structural base slab or may be separated by means of a sand cushion 14" thick and a layer of tarpaper. Structural cracks which occur in the base slab will not be transmitted to the terrazzo top course if this is separated from the base.

An underbed of 1:4 mortar, about 11/2" thick, is placed, and the dividing strips are inserted in the mortar in the desired pattern. When this has hardened sufficiently, the terrazzo mixtures consisting of 1 part of portland cement and 2 parts of aggregate are applied. The floor is


then rolled until thoroughly compacted, and after hardening sufficiently it is ground and polished.

Skilled labor working under adequate supervision is necessary for a good terrazzo job. The work should be entrusted to floor specialists whose experience has shown them capable of rendering the class of workmanship desired.

Concrete Tile

Beautifully colored, long-wearing fioors of precast concrete tile are used in residences, office buildings, hotels, churches, theatres, and similar structures. When made of marble chips and ground and polished, the tile are often referred to as art marble. The tile may be secured in many colors, shapes and patterns, and special designs may be made to order. They should be secured from reliable manufacturers.

When tile are to be installed, the concrete base course is brought to within 2 or 214" of the finished grad'e, left with a rough surface and allowed to harden. Mortar of 1:3 mix is placed on the dampened base, and the tile are laid in the desired pattern. Before the tiles are laid, they should be soaked in water for 10 or 20 minutes, and then allowed to dry for about the same length of time, the object being to have them uniformly damp, but not saturated with water. Tile should be laid by experienced mechanics.

Color with Pigments

A wide range of color is obtainable with the use of mineral coloring pigments mixed with the concrete finish. A single uniform color such as red, green or brown is most widely used in floors of this type, although a border of one color and field of another, as well as simple patterns involving two or more colors, has been used to some extent. '

Only pigments resistant to alkali should be used. Mortar colors containing a large percentage of filler are not suitable. Pure mineral pigments and factoryprepared mixtures of cement and mineral pigment are available for the purpose. Manufacturers directions should be carefully followed. Where mixing is to be done on the job, it should be very thorough to secure uniform dispersion and full color value of the pigment.

Various methods of mixing are used. The pigment may be added to the other dry ingredients and mixed thoroughly before the water is added. A color mixer or small ball mill may be used to mix the cement and pigment to a uniform color before these are added to the aggregate and water. Another method of mixing the pigment and cement is to pass them through a 14;" or finer sieve until the mixture is uniform. After all the ingredients are in the mixer, the batch should be mixed for at least 2 or 3 minutes and until it is uniform.

The color values of pigments vary with their fineness and purity. In comparing them, one should be guided by

TYPICAL CONSTRUCTION STEPS in building a colored concrete floor are shown here: I. after ecreedugg to proper level, dust-on color mixture is applied: 2. flouting forces mixture into surface: 3. steel-lrowelinq to a smooth surface; 4. troweling colored topping on two-course iobr 5. the troweled surface in brushed with core.
1950-51 Theatre Catalog, 9th Edition, Page 133