If the homeowner has a workshop in his garage or basement, you'll want to know what kind of work is done. If he restores antique cars, then the floor might be subject to oil spills, for example. Also in the garage, remember that tires get hot and heat softens paint. They also get wet and pick up gravel and dirt which are abrasive. Another problem you may encounter on a concrete floor is its finish, which may be troweled on so that it's hard and slick.
Concrete floors are more alkaline than walls.
The top layer is richer in cement because of the extensive finishing done to give it a smooth surface. Keep in mind, too, that concrete surfaces change as they go through the curing process. During the early curing stages, moisture content, lack of strength, and other surface conditions may adversely affect a coating's performance. The tools you use to paint concrete floors are similar to those used for other rough surfaces. Brushes, rollers, applicator pads, and spraying can be effective.