While a house is under construction, a homeowner has the opportunity to permanently improve the looks of his or her carport through the use of integral colorants in the concrete slab. Liquid or powdered colorant in a chosen hue can be added to the concrete as it is being mixed. The result is a uniform color throughout the carport slab. If a more natural, organic effect is desired, surface treatments which create marbleized, stone-like effects on the integrally-colored slab can be applied after curing or hardening is complete. A concrete sealant will prevent stains from being absorbed and will keep the colored concrete looking new.
The easiest way to improve the appearance of a concrete floor in a carport is to paint it. This can be done when the floor is new to prevent stains from penetrating the freshly-cured concrete, or it can be done to spruce up an older slab. Paint will cover defects such as stains and patched cracks with uniform color.
Specialized degreasers and cleaners should be used to clean the concrete and prepare it to receive paint. This step cannot be omitted; if concrete is not thoroughly cleaned, paint will not adhere to the surface and will peel. Water-based paint is easier to use, but oil-based is more durable. Epoxy is the best of all, but it is considerably more expensive. A couple of coats of sealant will enhance the appearance of the painted floor and extend its life.
Concrete stain is preferred by some over paint because it penetrates the concrete instead of coating it. There are several different types of stain, some easier to use than others. Acid-based stain is typically used for interiors. More suitable for a carport floor would be acrylic or water-based stains. Both of these are semi-transparent, but color can be intensified with repeated applications. While the dramatic effects of acid-based stains are not possible with acrylic or water-based stains, there are ways to achieve something more interesting than a uniformly-colored floor. Using a variety of applicators and layering different colors can yield attractive results. Sealing the concrete after staining will prolong the life of the floor and make it easier to clean.