Though some countertop contractors will not use lightweight concrete because it has less strength. Most building codes require a minimum design load for a floor of about 65lbs per square foot. A typical cabinet will support the concrete weight. Like most decorative concrete systems, you may choose from a wide range of colorings for your countertops. Each contractor will have different methods of coloring your countertop, ranging from integral coloring, broadcast color hardeners, and acid stainings.
Most contractors can custom color match samples.
No, the real beauty of using concrete as a material for your countertop is that each cast is unique. It's color, texture and porosity will vary depending on finishing technique, coloring, curing methods, and skill. This is often a debatable topic among our contractors but generally speaking, slabs should not exceed around 8' x 3'. Oversized slabs are usually hard to work with and are also more likely to crack. This just means that for large applications seams may be required but they can become a very attractive element of the design.