Renew Your Concrete Patio: How to Stain Concrete

Cut the Kerfs

Cutting kerfs is the most effective way to divide the patio into sections with different colors. Using tape isn’t an option because the stain will bleed underneath it and make a mess. If the concrete already has expansion joints, you can incorporate them into your design to avoid cutting kerfs.

When you cut kerfs, start by snapping a chalk line where you want to cut. The cuts need to be perfectly straight; crooked cuts will be obvious once you apply the stain. So, use a wide board as a saw guide and weigh it down with buckets of water.

Install a diamond masonry blade in a circular saw and set it to a depth of 1/4 inch to do the actual cutting. The cuts don’t need to be deep — just enough to separate colors. Have a helper spray a water mist on the blade during the cut to contain the dust.

• Pro tip: Don’t use a cheap abrasive blade — you can’t spray it with water, and you’ll end up with dust all over your siding and windows.

You won’t be able to get the saw blade right next to the house, so finish off the kerfs with a masonry chisel and a hammer or a grinder with a diamond blade.

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Clean Up, Rinse and Plan the Color Scheme

As with any other staining concrete project, surface preparation is critical. Any stains, such as rust, will show through in the finished project. To clean your patio:

Scrub the concrete with a stiff broom to remove dirt. Then, rinse the entire patio with water. Now, clean the entire surface with a heavy-duty cleaner, working in 4 x 4-foot sections at a time, then rinse the concrete with water until you don’t see any more soapy bubbles. For tough rust stains, use a stain remover and rinse it off with water. For grease or oil stains, use a product that’s designed to remove those stains. Blast dirt and debris out of the kerfs with water.

Here are a few more tips for cleaning your concrete patio:

• This project will proceed much faster and easier if you stain your whole patio a single color. All you have to do is wet the concrete, apply the stain and back roll with a 3/8-in. nap roller to get even coverage. That’s it—there’s no need to block off sections or switch sprayers.
• If you want a pattern with different colors, start by deciding on a color scheme. Anywhere you want to switch from one color to another, such as for a border or for the checkerboard pattern shown here, you’ll need a kerf to give the colors a crisp separation.

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Prep for Staining

Now that the concrete is clean, make sure your shoes are, too, before you walk on the patio again. Because the surrounding ground is wet from all the soap and water, I always change into a pair of clean, dry shoes that I wear only when I’m walking on the patio.

Before cracking open the stain, shield the lower portion of the house and any nearby landscaping materials against drifting spray. Tape plastic film along the siding. You don’t necessarily have to protect plants and grass if you don’t want to because any stain that gets on them will hardly be noticeable. I like to do it anyway, and I use burlap instead of plastic to allow the vegetation to breathe.

If dirt remains on the patio after you’ve cleaned it, brush the concrete lightly with a broom to prevent the dirt from pushing into the surface.

Apply the Base Coat

If you’re painting your entire patio a single color, the base coat is the only coat you’ll need to apply, so any color is okay. However, if your project is similar to ours, your plans might include more colors. If so, you’ll be spraying them over the base coat, so in this case, it’s best to choose a light color.

Wet down the concrete, pour the stain into a garden sprayer, and spray enough to cover the entire surface. To keep the distribution uniform, move the sprayer wand in a continuous circular motion as you go.

When you’re done, back-roll the entire patio with a 3/8-in. nap roller to distribute the stain evenly and pick up any that doesn’t soak in.

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Add a Second Color

Create a marbleized look by spraying on a second color while the first color is still wet. To do this effectively, work in small sections (4 x 6 feet or so), starting near the house and working outward. Plan the application so you don’t box yourself into a corner. Don’t worry about getting even coverage — you want the colors to mix together, so there’s no need to back-roll.

Here’s the procedure in a nutshell:

1. Spray a section of the concrete with water, getting it completely wet but leaving no standing water.
2. Have a helper hold shields in the kerfs to prevent spray from staining adjacent sections. We used fluorescent light lenses (available at home centers), but you could also use cardboard. Have four or five shields on hand, so you don’t have to use one that’s dripping wet with stain and watch it drip stain into places you don’t want it.
3. Spray the base coat in a circular pattern. Before it dries, mist more water over the section and spray the second color. The first and second colors will intermix, producing the marbleized effect.
4. Use the water to “push” the color all the way to the edges or onto bare spots. If the water pools in a low spot or starts to run onto an adjacent section, dab it up with a cloth.

When switching to a new stain color, be sure the shields are dry, or use new shields to prevent colors from dripping onto other patio sections. Don’t worry if a leaf or debris blows onto the wet stain. After the stain dries, remove the debris and touch up the stain.

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Blend the Colors with Water

Finish creating the marbleized look by blending the first and second colors together with water. Use the water stream to push the stain to bare spots and to produce swirls in the stain. There’s no “right” way to do this. In fact, everyone will do it a little differently, so this is where you can exercise your creativity.

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Add More Colors

Add another color, or two more if you like, to create a more complex pattern. To do this, you apply the base coat as before, then spray the colors at the same time and intermix them with water. You’ll need a separate sprayer for each color, but they don’t necessarily have to be garden sprayers. Handheld plant sprayer bottles will work for the colors. Fill the sprayers over tarps on the grass — you don’t want spills to stain the concrete.

• Caution: Concrete staining isn’t a job to do in direct sunlight because the stain will dry too fast. If the patio isn’t shaded, wait for a cloudy day. You should also wait for a windless day because winds will make the spray drift.

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Touch Up with a Cloth

After the surface is dry, look for bare spots. Touch them up by spraying the stain from a hand-held spray bottle onto a clean cloth, then dabbing the stain onto the spots. Dab the surrounding area so the stain blends naturally.

Let the stain dry for 24 hours. If the color isn’t as vibrant as you want or the coverage is spotty, go back and add another coat of stain. Wet the concrete and apply the stain using the same steps as before. We added a second coat to the corner squares of our patio to give them a deeper, richer color.

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Seal the Deal

Your freshly stained patio will look vibrant right after the stain dries, but it won’t stay that way for long unless you seal the concrete. For this, I use any good-quality, water-based polyurethane or acrylic concrete sealer — as far as I can tell, acrylic and polyurethane are equally durable.

Give the stain a full day to dry, then apply the sealer. Choose a day or time of day when the patio is shaded (don’t apply the sealer in direct sunlight). Start by cutting in with sealer along the patio edges with a 3-in. brush. The milky white sealer turns clear as it’s applied. Roll sealer on the rest of the patio with a 3/8-in. nap roller. Let the sealer dry for two hours, then apply a second coat. Roll the second coat perpendicular to the first coat.

The sealer will dry in a couple of hours, but just to be safe, wait overnight before walking on the patio.

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FAQs

What types of stains are available for concrete?

There are generally two types of concrete stains: water-based and acid-based. You can also purchase acetone-based dyes.

• Water-based stains, like the type used in this project, consist of fine particles that settle into the pores to give the concrete color. They are easy to apply and clean up and have a wide color selection.
• Acid-based stains react with concrete to permanently change its color. They are slightly more troublesome to apply, and color selection is limited.
• Acetone-based dyes come in liquid and powder form. They work like water-based stains, but the pigment particles are smaller and produce more vibrant colors. Dyes break down in UV radiation and are generally suitable only for indoor surfaces.

What are the benefits of staining a concrete patio?

Here are some reasons why you might want to consider staining your patio:

• The process doesn’t require much skill, and materials are inexpensive.
• You get quick results.
• A stained and sealed patio will withstand the weather better than an unsealed one and may very well last longer.
• Staining can help mask imperfections in the concrete, although it won’t hide them completely.
• Vibrant colors add a touch of class to your outdoor space.