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1950-51 Theatre Catalog, 9th Edition, Page 126 (106)

1950-51 Theatre Catalog, 9th Edition
1950-51 Theatre Catalog
1950-51 Theatre Catalog, 9th Edition, Page 126
Page 126

1950-51 Theatre Catalog, 9th Edition, Page 126

A Detailed Study of Concrete Floors

The Basic Ideal Type of Surface for Theatres and Its Kin, Such as Terrazzo, Are Treated at Length

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THE CORRECT PROCEDURE in the construction of concrete floor finishes begins (above) with: l. accurate proportions of ingredients: 2. rougheniug of base slab. BELOW: 3. manipulation of surface for durability; 4. delayed troweling.

Due to the many reasons of fire safety, maintenance economy, accident prevenr tion, wearing capacity under heavy traffic, and sanitation, all floor surfaces in motion picture theatresfrom the sidewalk through the lobby, foyer, auditorium, stairways, balcony, lounges, and toilet rooms, must need be either concrete terrazzo, or some other monolithic hard substance. While it is true that trafhc areas inside of the theatre, such as foyers and aisles, must be heavily carpeted to reduce traffic noises, the largest areas of the interior remain uncovered and, therefore, present many rather unusual construction and maintenance problems.

BRIEF: Although the informative surveys to date in. the preceding annual volumes of THEATRE CATALOG have covered hundreds of subjects . . . of either continuing or permanent merit . . . hard floor surfaces have never been thoroughly analysed . . . nor have recommendations been made for their original installation . . . or later care and maintenance . . . Naturally, references have been made to them as they affected structure, sight lines, or the installation of equipment . . . but that is about all.

In order to add a thorough review of this important topic to the vast fund of knowledge . . . on all subjects pertinent to the physical aspects of the theatre . . . already contained in its pages, the Editors of THEATRE CATALOG have undertaken an exhaustive survey of concrete . . . and related types . . . of floors for motion. picture houses . . . A minutely detailed analysis has been made of such matters as: construction of the base slab . . . finishing procedures . . . decorative concrete floors . . . covered floors . . . and maintenance.


First and foremost among the various types of fioors available for theatre use stands the ordinary concrete one with its many advantages ranging from moderate first cost to low insurance rates. A properly built reinforced concrete floor will last indefinitely and require little maintenance. Since, in the final analysis, other species of fioors suitable for theatre installation, such as terrazzo, are actually odshoots of the basic concrete type, it is important that the theatreman fully understand the correct procedures for constructing, installing, finishing, and maintaining a concrete fioor that may reasonably be expected to yield years of faithful service. While other types of floors will be briefiy touched upon, the basic concrete one will be the focal point of discussion throughout this survey with particular attention to its application to theatre floors either by itself or in combination with other floor finishes.


Where floors are subject to constant wear and require frequent cleaning, as in theatres, the two-course fioor, which consists of a structural base slab and a wearing course 1%" to 1" thick placed over it, is recommended (on auditorium floors, however, a wearing course 2" thick must be used to accommodate standard 1%" anchor bolts for chairs). Inasmuch as the former is the basic surface on which the latter is imposed, it seems advisable to analyse it thoroughly first of all before proceeding to a discussion of wearing courses, or ftfinishes," as they are more generally called. An examination of the base logically begins with a definition of concrete and the conditions required for the durability essential in the construction of floors.

Definition of Concrete

Concrete is a mass of line and coarse materials, known as ffaggregatesfl which are surrounded and held together by hardened portland cement paste. If the paste is strong and the aggregates durable, the concrete is strong. If the paste is watertight, the concrete is watertight. If the paste and aggregates are durable, the concrete is durable.

When the materials for concrete are first mixed together, the cement and Water form a paste. The paste surrounds the particles of aggregate and holds them together to form concrete. This concrete is in a plastic condition. A chemical action then takes place between the cement and water causing the paste to harden.

If strong concrete is desired, the paste must have high strength when hardened. During mixing, if too much water is added, the paste becomes thin or diluted and will be weak when it hardens. A paste of this kind will not hold the particles of aggregate firmly together. When the paste is weak the concrete will be weak because the pieces of aggregate will be only partially held together. On the other hand, cement paste which has good binding qualities will hold the particles of aggregate firmly together to make strong concrete. Therefore, the water and cement are the important ingredients in a concrete mixture.

It is known that the quality of the portland cement paste used determines how strong, how watertight, and how durable hardened concrete will be. The quality of this paste is determined by the quantity of water mixed with the cement, and this is the main reason why concrete is now proportioned according to the amount of water to be mixed with each sack of cement.

Selection of Materials

Choosing suitable materials is the first step in making concrete that is to be

1950-51 Theatre Catalog, 9th Edition, Page 126