Pouring concrete for a patio is a multi-day project that requires careful preparation, the right tools, and attention to slope and finishing
A concrete patio starts with a solid foundation and proper grading so water drains away from your house. The actual pour takes one day, but you'll spend two to three days preparing the site, building forms, and letting the concrete cure. The concrete itself is mixed on-site or delivered ready-made, spread into wooden frames, leveled, and finished with a broom or trowel. Most DIY patios are 4 inches thick and slope slightly downward at about 1/8 inch per foot.
This is a project you can do alone if your patio is under 100 square feet, but a helper makes the work faster and safer. Expect to rent or buy a wheelbarrow, shovel, level, and concrete finishing tools. The concrete costs roughly $3 to $8 per square foot depending on your region and whether you mix it yourself or have it delivered.
Key Takeaways
- Mark out your patio area and dig down 4 to 6 inches, removing grass and roots, then compact the soil firmly with a hand tamper or plate compactor.
- Build wooden forms (frames) around the perimeter using 2-by-4 lumber, staked level and square, so the concrete has a boundary to fill against.
- Slope the forms slightly downward away from your house at about 1/8 inch per foot so rainwater runs off instead of pooling.
- Pour concrete into the forms, spread it with a shovel, strike off the excess with a straight board, then finish the surface with a broom or trowel depending on the texture you want.
- Keep the concrete moist for at least three days after pouring so it cures evenly and reaches full strength without cracking.
Prepare the site and check drainage
Start by marking the outline of your patio with chalk or string. Measure from your house and mark the corners with stakes. Use a 3-4-5 triangle method to check that corners are square: measure 3 feet along one side, 4 feet along the other, and the diagonal should measure 5 feet. If it doesn't, adjust the stakes until it does.
Dig out the area to a depth of 4 to 6 inches. Remove all grass, roots, and loose soil. Compact the bottom with a hand tamper (a flat metal plate on a handle) or rent a plate compactor for larger areas. The soil should be firm enough that your foot leaves only a shallow impression. Loose soil will settle after the concrete is poured, causing cracks and uneven surfaces.
Check the slope of the ground from your house outward. The patio should slope away so water doesn't pool against the foundation. You'll fine-tune this slope when you build the forms, but the natural ground should already tilt slightly downward.
Build and level the wooden forms
Use 2-by-4 lumber to build a frame around the perimeter of your patio. Cut the boards to length and position them inside your marked outline. Drive wooden stakes (2-by-2 or 2-by-3 lumber, cut into 18-inch lengths) on the outside of the frame every 3 to 4 feet, then nail or screw the form boards to the stakes. The top of the form board is where the concrete surface will be, so this must be level and at the correct height.
Use a 4-foot level to check that the forms are level side-to-side (perpendicular to the house). For the slope away from the house, use a level with a slope gauge or calculate the drop: a 10-foot-wide patio should drop 1.25 inches from the house side to the far side. Mark this height on the stakes and adjust the form boards up or down until they match. Nail the boards securely so they won't shift when you pour concrete against them.
Double-check that the corners are square by measuring the diagonals again. Both diagonals should be equal length. If they're not, loosen the stakes slightly and shift the frame until they match.
Mix or order concrete and prepare to pour
For patios under 50 square feet, you can mix concrete in a wheelbarrow or rent a concrete mixer. Bags of concrete mix (usually 60 or 80 pounds each) are available at hardware stores. Follow the bag instructions for water ratios—too much water weakens the concrete, too little makes it stiff and hard to spread.
For larger patios, order ready-mix concrete delivered by truck. Call local concrete suppliers and tell them the square footage and thickness (4 inches). They'll quote a price per cubic yard and a delivery fee. Ready-mix is faster and produces more consistent results, but you must be ready to pour when ready when the truck arrives—concrete begins to set within two hours.
Before the pour, have all your tools ready: a wheelbarrow, shovel, straight board (a 2-by-4 or 2-by-6 longer than your patio width), a level, a concrete finishing trowel, and a broom. Wet down the soil and forms lightly so they don't absorb water from the concrete. Have a helper on hand if possible—pouring concrete is fast work and you'll need someone to move material while you spread and finish.
Pour and spread the concrete
Start pouring concrete into one corner of the form and work your way across. If mixing bags, pour each batch into the form and spread it with a shovel before adding the next batch. If using ready-mix, the truck will pour directly into the forms—direct the chute and have your helper guide the flow so it spreads evenly.
Spread the concrete with a shovel, working it into corners and against the form boards. Tap the outside of the forms with a rubber mallet to release air bubbles trapped in the concrete. These bubbles create weak spots and rough surfaces. Work the concrete until it fills the entire form and is roughly level with the top of the boards.
Use a straight board (called a screed board) to strike off excess concrete. Place the board flat across the top of the forms and drag it toward you in a sawing motion, letting the board ride on the form tops. This levels the surface and removes excess concrete. You may need to make two or three passes, adding concrete to low spots and striking off again.
Finish the surface while concrete is still wet
Once the surface is struck off level, you can finish it in several ways. For a non-slip surface, drag a stiff broom across the concrete in parallel lines. This creates a textured finish that's safer when wet. For a smoother finish, use a concrete finishing trowel—a flat metal blade on a handle—to smooth the surface in overlapping strokes.
Work quickly because concrete begins to set within 30 to 60 minutes depending on temperature and humidity. On hot days, it sets faster. If the surface is still very wet and shiny, wait a few minutes for some water to evaporate before troweling.
Smooth the edges by running a concrete edging tool (a small metal blade) along the perimeter where the concrete meets the forms. This rounds the edges slightly and prevents chipping. If you want a broom finish, do the edging first, then broom the main surface.
Remove forms and cure the concrete
Leave the forms in place for at least 24 hours so the concrete sets enough to support its own weight. After 24 hours, carefully remove the stakes and form boards by tapping them gently with a hammer. The concrete should be hard but not fully cured.
Keep the concrete moist for at least three days after pouring. Spray it lightly with water twice a day or cover it with plastic sheeting to slow evaporation. Concrete cures by a chemical reaction with water, and keeping it moist ensures even, strong curing. Rapid drying causes surface cracks.
Do not walk on or place weight on the patio for at least three days. Light foot traffic is usually safe after one week, but the concrete continues to gain strength for up to 28 days. Avoid heavy loads (vehicles, equipment) for at least two weeks.
Common mistakes to avoid
The most common error is not sloping the forms correctly, which leaves water pooling on the patio surface. Check the slope with a level and slope gauge before pouring, and verify it again after striking off the concrete.
Pouring on unprepared soil causes settling and cracks. Compact the base thoroughly and remove all loose material. A hand tamper works for small areas, but rent a plate compactor for anything larger than 100 square feet.
Finishing too early, when the concrete is still very wet, causes the surface to become rough and uneven. Wait until the surface is firm enough that your finger leaves only a shallow impression before troweling or brooming.
Letting the concrete dry too fast causes surface cracks. Keep it moist for three days, especially in hot or windy weather. Covering it with plastic is the easiest method.
Frequently Asked Questions
Can I pour concrete in cold weather?
Concrete sets much slower in cold weather and can freeze before it cures, which ruins it. Avoid pouring when temperatures are below 50°F or dropping below 40°F at night. If you must pour in cool weather, use concrete additives designed for cold weather and cover the finished patio with plastic and blankets to retain heat.
What if I get cracks in the concrete after it cures?
Small hairline cracks are normal and don't affect the patio's strength. Larger cracks (wider than 1/4 inch) can be filled with concrete crack filler or caulk. Clean out the crack with a wire brush, explore the filler, and smooth it level with a putty knife.
How thick should a concrete patio be?
Four inches is standard for residential patios that won't support vehicles. If you plan to park a car on part of the patio, pour that section 5 to 6 inches thick. Thicker concrete is stronger but costs more and requires more material to excavate and prepare.
Do I need a permit to pour a concrete patio?
Many cities require a permit for patios, especially if they're larger than a certain size or close to property lines. Check with your local building department before you start. A permit usually costs $50 to $200 and involves a straightforward inspection to may support the work meets code.
Can I pour concrete directly on grass?
No. You must remove all grass and roots and compact the soil beneath. Grass will decompose under the concrete, creating voids that cause settling and cracks. Dig down at least 4 inches, remove all organic material, and compact the base firmly.