Before there is any thought of laying a concrete floor, it is good to take a long look at the type of exposure to which it may be subject. A good concrete floor must be even better built than a road. This is because of the use a floor gets. An industrial floor must be prepared to take punishment form sharp, small wheeled trucks and heavy vibrating machinery, and impact and abrasion form an endless variety of containers and products. There are five essentials of good concrete floor construction. Preparation of the subgrade is important because the strength of a floor is only as good as the quality of its base. A firm uniform base, uniformly compacted, is essential since slab design is usually mad on the assumption of uniform bearing capacity. Proper slab design is a complicated subject involving many factors including soil-bearing capacity, strength of mix, and the area and position of the static and dynamic loads applied. As a general rule thought the minimum satisfactory thickness of a thin slab is 5 inches. Reinforcement is not necessary but does help prevent cracks. The basic mix should by made with hard, well-graded aggregates and should contain only sufficient water to insure good workability. Good practices should be observed when placing the concrete, finishing and curing.