Not only can overlays disguise defects and add stone-like textures to concrete surfaces by creating a stamped concrete floor, but they can also be dyed or stained a variety of colors. Fairly uniform colors are possible as are variegated and marbleized effects. Colored pigments can be added to the overlay mixture while it is being mixed; which is called integral color; this creates a more uniform look overall. The overlay mixture's natural color is an off white, so adding a small amount of pigment tends to create a light color, more pigment creates darker colors. Staining, meanwhile, creates a far more variegated look. Stains are applied to the concrete surface after the concrete has hardened, these only change the color of its surface. Before choosing the best method and color, you may want to consider the benefits and disadvantages of dark and light colored concrete. Lighter and darker colors have very different qualities as you'll see below.
Light colored concrete is cooler in temperature than dark colored concrete. Sunlight heats the concrete, so this is only an issue with outdoor concrete surfaces; indoors, there's no real difference in temperature between light and dark concrete. In direct sunlight, concrete can reach temperatures between fifty and ninety degrees Fahrenheit hotter than the ambient air temperature. In the United States during the summer, paving materials can reach temperatures of 120 to 150 degrees Fahrenheit. This heating effect is so common that large metropolitan cities are often called "heat islands". The large expanses of concrete absorb sunlight during the day increasing the overall temperature and maintaining it long after the sun has set. This scenario doesn't exist in rural areas, where fewer surfaces are covered in concrete.
These temperature discrepancies apply to both regular concrete and stamped overlays with color being the main determinant as to its temperature. Overlays can actually be cooler than regular concrete, as long as the overlay has a light coloration. We have experienced this firsthand. At this Texas home, we poured an overlay for a stamped concrete floor. Part of the patio was left untouched. We lightly tinted the overlay material prior to staining it and, out of curiosity, we decided to do a little experiment. I took off my shoes and socks, placed one foot on the stamped concrete floor and the other foot on a section of regular concrete. The regular concrete was so hot I could barely keep my foot on it while the stamped portion was just fine, no problems. If the stamped concrete floor had been stained a dark color, then it too would have been too hot to stand on.
We aren't big fans of a darkly stained stamped concrete floor, the darker the stain, the more it tends to show dust, footprints when you walk over it, etc. There are a few benefits to a dark-colored concrete surface. During winter months, dark concrete can melt ice and snow faster than light concrete, though that's obviously not a really big concern here in Texas. Dark colors do lend an elegant, formal appearance to a stamped concrete floor and can hide imperfections in the floor, such as damage caused by abuse or accidents.
Light or medium colored stamped concrete floors, meanwhile, can feel cooler during summer months and tend to hide dirt a little better. There are advantages and disadvantages to both dark and light colors. Which way to go is your decision.