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Before painting your patio, make sure that paint will adhere in the first place. All concrete is porous and absorbs moisture, but if your concrete patio contains too much moisture, you won’t be able to paint it until you correct the moisture content.  Take an 18-inch by 18-inch square of aluminum foil or thick plastic and tape down all four sides, sealing the square to the concrete with tape. Wait 16 to 24 hours. After that time, carefully remove the square of foil or plastic and check the concrete and the underside of the square for condensation or moisture. If the concrete is still damp, wait until weather allows complete drying. Protect the area from sprinklers and garden runoff. Proceed once the concrete is completely dry. Since you are painting concrete in an outdoor area, not just any paint will suffice. Regular exterior paint will likely crack on a concrete surface and peel off shortly after being applied. There are several types of paint that will work for your outdoor concrete patio, and they include:  Concrete paints that contain sealants or waterproofing features, so the paint is designed to resist water, salt, oil, and grease. This is a good choice for paint because it's specifically designed for outdoor concrete and resistance to various substances and elements. Latex, water-based, or oil-based exterior paints that are designed for floor, patios, or porches. These paints are also a good choice, as they are designed for exterior use and are specific to withstand foot traffic. Masonry paints that contain added binders and epoxies. While it may bond well with the concrete, it won't necessarily protect your concrete from the elements. Garage floor coatings with colorful additives to protect and decorate at the same time. To help you decide what color to paint your patio, consider what color the exterior of your house is, and what color your patio furniture is. Take color swatches with you to the paint store so you can compare your existing decor with your paint choices. Don't be afraid to ask the paint specialist for help and advice! A concrete or block primer will give you a nice, even surface to work with, instead of the uneven, porous surface of non-primed concrete. It will also reduce the number of coats required to properly cover your surface. Choose an exterior-grade primer if you’re going to use one, and make sure it’s designed for concrete. Concrete primers are often called concrete, masonry, or bonding primers. Once you’ve decided what kind of paint you’re going to use, you will need to do some basic calculations to determine how many cans of paint you’ll need to cover the patio surface. Check the paint can or manufacturer's website regarding how much coverage one can provides, and compare that with the square footage of your patio.  Square footage is determined by multiplying the length by the width of the area you are dealing with. Don't worry if your patio isn't perfectly square or rectangular: you just need a basic idea of the area you're going to cover. Don't forget to take into account whether you plan on applying multiple coats. A primer will reduce the likelihood of having to apply more than one or two coats of paint. Before getting started, get together all the tools you’re going to need for painting. The best painting tools for this will be a masonry brush, a high-capacity roller, or a texture roller. The equipment you’ll need may include:  Primer (optional) and paint A paint roller frame and cover A paint tray Roller and brush extenders Masking or painter’s tape Thick and thin brushes Plastic or painter's tarps Use tape to line the surfaces touching your concrete patio, such as deck edges, exterior walls, doors or windows, and other areas that you don’t want to accidentally paint. Cover the ground nearby with tarps if necessary. Ideally, begin painting on a dry day when there has been no rain in the previous 24 hours, and none is expected in the long-range forecast. The best temperature for outdoor painting is about 50 F (10 C).
Test the concrete for moisture content. Select your paint. Choose a color. Consider using a primer. Determine how much paint you need. Assemble your tools and equipment. Protect your surfaces. Choose the right day.