One drawback is that in its natural state, it's gray and textureless -- and to many, it presents an uninspiring face. By applying coloring and stamping techniques, however, poured concrete can be made to look like flagstone, brick, or cobblestone at a fraction of the cost of the real thing. Embedding the surface with aggregates increases your design possibilities even further and can create a dazzling concrete surface.Designing with concrete
In one sense, concrete has unlimited design potential, which makes it a useful material in both formal and informal design schemes. The material itself is considered design-neutral. Coloring, forming, and stamping or texturing give it its final surface quality. Concrete is also a perfect base for a variety of surface materials, partly because it conforms to variations in grade. Properly mixed and cured, it requires little maintenance.
A concrete installation, however, requires careful planning and, for large projects, heavy equipment and helpers. Most important, concrete has a specified working time, which is affected by weather conditions and can be altered to some degree with additives. Once that working time is up, you can't correct mistakes easily or inexpensively.
It is the substrate material of choice for all mortared paths and patios, providing a strong, level, and stable base for brick, tile, and stone.Dressing up an old slab
Plain concrete slabs used to be the standard for a patio, and there was a time when almost every new home came with a concrete slab in back. Some still do.
If your house has one and you have thought about tearing it out, consider other solutions first. If the slab is in the right location and is structurally sound, with a surface in good repair, you have a ready-made base for a mortared brick, tile, or flagstone patio. Using the existing slab will save you money, time, and effort.
If the slab is structurally sound but its surface is chipped or cracked, you can resurface it and mortar on a finished paving material. If a mortared surface is not in your plans or budget, you can easily add color to it.
Concrete stain offers the quickest facelift. Most home centers carry a variety of stains, some which produce an attractive, mottled finish. These coloring agents hide other stains and blemishes, too, especially if you use darker colors. Darker hues also help blend in the patio or walk with the rest of the landscape and cut down on glare from the sun.
You'll need several coats to produce a rich color. To create a mottled effect to downplay minor imperfections in the surface, apply the first coat evenly; then dab on subsequent coats unevenly with a sponge. Some dyes will etch the concrete and are caustic. Protect your hands with rubber gloves and your eyes with safety goggles. You can apply stencils to create accents within the perimeter. If you want to go all out, have a pattern cut in the concrete surface with a diamond saw before you stain it. Look in the Yellow Pages for a professional who can do this for you.Installing a poured-concrete wall
Pouring concrete into prefabricated forms is a popular method for building both freestanding and retaining walls. You can rent the aluminum forms and assemble them yourself, but a small crew of helpers is recommended. Three or four workers can put up the forms for a 12-foot wall in less than a day. The forms have to come off when the concrete is cured, but that takes about half the time of assembly.
Poured concrete for walls is available in various colors as are forms that leave patterns imprinted in the face of the wall.Open and closed concrete stamps
A concrete stamp with a closed top textures the surface, here giving the look of stone. Open-top stamps impress a shape but not a texture into concrete. You can combine any stamp pattern with a color.Concrete options
Mix the concrete from scratch, or order it ready to go. The choice is yours.
Bulk dry ingredients: You can buy the cement, sand, and aggregate separately and mix them with water in a mortar box, wheelbarrow, or rented concrete mixer. Mixing concrete is heavy work, but for medium-size jobs it's economical.
Premix: An easier but somewhat more expensive alternative is to buy concrete mix, i.e., bags with the dry ingredients already mixed in the correct proportions. You just add water, mix, and pour. Premix takes the guesswork out of mixing -- but not the effort. It makes jobs under a cubic yard manageable (you'll need 40 or more bags for a cubic yard, depending on the weight of the bags), but for anything larger than that, order ready-mix.
Ready-Mix: Ready-mix relieves you of the mixing process but requires a quick and experienced work crew. Your site must be accessible to the mixing truck and ready for the pour as soon as the truck arrives. You can order ready-mix with additives that make it workable in a variety of weather conditions.Pro Tip: Buying concrete
Buy bags of premix concrete at hardware stores, home centers, lumberyards, or building-supply centers. Order bulk ready-mix concrete from a ready-mix concrete company. Buy dry ingredients (portland cement, sand, and aggregate) to mix it yourself at any of the above outlets.
To estimate how much you'll need, compute the volume of your project (multiply length times width times depth in the same units). Then add 5 percent to this amount.
A 40-pound bag of premix makes 1/3 cubic foot.
A 60-pound bag makes 1/2 cubic foot.
An 80-pound bag makes 2/3 cubic foot.
A 4x20-foot walk that's 4 inches (1/3 foot) deep requires 26-2/3 cubic feet of concrete. (One cubic yard is 27 cubic feet.) For quantities over a cubic yard, order ready-mix.