What You Need to Know Before You Start
A cement patio is a concrete slab poured on a prepared base of gravel and sand. The work breaks into three main phases: preparing the ground, building the frame and pouring the concrete, and finishing the surface. Most homeowners can handle a small patio (under 200 square feet) in a weekend with help, though the concrete needs time to cure before you can walk on it. Larger projects or sloped terrain often benefit from professional help, especially if you need proper drainage or the ground is uneven.
The biggest variable is whether your ground is already level and stable. If you're pouring over soft soil, clay, or an old patio you're breaking up, the prep work takes longer and costs more. If you're working on compacted ground or an existing level surface, you can move faster. Either way, the concrete itself is the same process.
Key Takeaways
- Prepare the ground by removing grass or old concrete, compacting the soil, and laying 4 inches of gravel as a base to prevent water from pooling under the patio.
- Build a wooden frame (called a form) around the perimeter using 2-by-4 lumber, staked level and square, to hold the concrete in place while it sets.
- Mix concrete in batches or order ready-mix delivered by truck, pour it into the frame, and spread it level using a long straight board.
- Finish the surface by smoothing it with a trowel, adding a broom texture for traction, and letting it cure for at least 7 days before walking on it.
- Rent or borrow a tamper and wheelbarrow to save money on tools you'll use only once.
Preparing the Ground and Building the Base
Start by marking out the patio area with chalk or spray paint. Remove all grass, weeds, and debris down to bare soil. If there's an old concrete patio you're replacing, you'll need to break it up with a sledgehammer or rent a concrete breaker—this is heavy work and worth paying a rental company to deliver and pick up the tool. Haul away the broken concrete; don't bury it under the new patio.
Once the ground is bare, check the level with a long straight board and a 2-foot level. Mark the high and low spots. You want the finished patio to slope very slightly (about 1/8 inch per foot) away from your house so water runs off instead of pooling. Dig down the high spots and fill the low spots, then compact the soil firmly with a hand tamper or rent a plate compactor for larger areas. Loose soil will settle under the weight of the concrete and crack it.
Spread 4 inches of gravel over the compacted soil and tamp it down. This base layer lets water drain away instead of sitting under the patio. Rake it level, then lay landscape fabric over it to keep sand from mixing into the gravel.
Building the Frame and Checking Square
The frame (called a form) holds the concrete in place while it cures. Use 2-by-4 lumber, either new or used—used boards are cheaper and work fine. Lay them around the perimeter of your marked area, with the inside edge defining the patio edge. Drive wooden stakes on the outside of the frame every 4 feet, then nail or screw the boards to the stakes.
The frame must be level side to side and sloped slightly front to back (away from the house). Use a 4-foot level to check. Adjust the stakes up or down until the board is level across, then check the slope with the level placed lengthwise—it should show a very slight tilt, about 1/8 inch drop per foot of length. This is easier to see than to measure; if water would run off it, the slope is right.
Check that the corners are square by measuring diagonally from corner to corner. Both diagonals should be the same length. If they're not, loosen the stakes and nudge the frame until they match. Once the frame is level, square, and sloped correctly, nail the stakes firmly so they won't shift when you pour.
Ordering or Mixing the Concrete
For a patio under 100 square feet, you can mix concrete in batches using bags of concrete mix and a wheelbarrow or mixer. A standard 60-pound bag makes about 0.45 cubic feet of concrete. For a 4-inch-thick patio, you need roughly 1.2 cubic feet per 10 square feet, so a 100-square-foot patio needs about 12 bags.
For anything larger, order ready-mix concrete delivered by truck. A ready-mix truck delivers concrete already mixed to the right consistency and can pour directly into your frame. Call local concrete suppliers and ask for a quote based on your patio size and thickness. Most charge by the cubic yard. A 100-square-foot patio 4 inches thick needs about 1.2 cubic yards. The truck can usually back up to your site, but confirm access before ordering—if the truck can't reach your patio, you'll need to hand-carry concrete in wheelbarrows, which is slow and exhausting.
If you're mixing bags, follow the instructions on the bag. Generally, you'll mix the dry powder with water until it looks like thick oatmeal—not soupy, not crumbly. Work in batches and pour each batch into the frame before it starts to set.
Pouring and Spreading the Concrete
Pour the concrete into the frame, starting at one corner and working toward the opposite corner. Spread it roughly level with a shovel, then use a long straight board (a 2-by-4 works well) laid across the top of the frame to screed the surface. Two people work best: one pushes the board forward in a sawing motion while the other guides it. The board should be slightly longer than the patio is wide so it rests on the frame on both sides. Screed the entire surface until it's level with the top of the frame.
After screeding, the concrete will have air pockets. Tap the sides of the frame with a hammer or use a vibrating screed board (if you rented one) to shake out the air. This makes the concrete denser and stronger. Work your way along the entire patio.
Let the concrete sit for 20 to 30 minutes. It will firm up slightly. Then smooth the surface with a steel trowel, working in long overlapping strokes. You don't need a mirror finish—a slightly rough surface is safer to walk on.
Finishing and Curing
Once the surface is smooth, add texture for traction. The easiest method is to drag a stiff broom across the surface in one direction, creating parallel lines. Do this while the concrete is still slightly soft but firm enough that the broom doesn't sink in—usually 30 to 60 minutes after pouring. If you wait too long, the concrete hardens and the broom won't mark it. If you go too early, the broom sinks too deep.
You can also leave the surface smooth (slippery when wet), add a non-slip coating later, or create other patterns with a broom or brush. The choice is yours, but textured surfaces are safer for patios.
Once you've finished the surface, cover the patio with plastic sheeting or burlap to slow evaporation and help it cure evenly. Concrete cures by chemical reaction, not by drying, so keeping it moist helps. Mist it with a hose every few hours for the first day, then once or twice daily for at least 7 days. Don't let it dry out completely during this time. After 7 days, you can walk on it. After 28 days, it reaches full strength and you can move heavy furniture or equipment onto it.
When to Call a Professional
If your ground is very uneven, slopes significantly, or has poor drainage, a professional can assess whether the site needs grading, a thicker base, or a different approach. If you need to remove an old patio and the concrete is thick or reinforced with rebar, breaking it up is hard physical work—renting a breaker and doing it yourself saves money, but hiring a demolition crew is faster.
If your patio is larger than 300 square feet, has a complex shape, or needs to tie into existing structures, a concrete contractor can handle the whole job and may provide the result. For a small, straightforward rectangular patio on level ground, most homeowners can do it themselves with help and basic tools.
Frequently Asked Questions
How thick should a patio be?
Four inches is standard for a residential patio that will support foot traffic and light furniture. If you plan to park a car or heavy equipment on it, go to 5 or 6 inches. Thicker concrete costs more but lasts longer under heavy use.
Can I pour concrete in cold weather?
Concrete sets slower in cold weather and can be damaged by freezing before it cures. Avoid pouring when the temperature is below 50°F or expected to drop below freezing within 24 hours. Spring and fall are ideal; summer heat can cause the concrete to cure too fast and crack.
What if the concrete cracks 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 sealed with concrete crack filler to prevent water from getting in and freezing, which makes them worse. If cracks are widespread or the patio is sinking, the base may have settled unevenly—a concrete contractor can assess whether it needs repair.
Do I need a permit to pour a patio?
Many cities require a permit for any concrete work, especially if it's near property lines or utilities. Call your local building department before you start. A permit usually costs $50 to $200 and involves a straightforward inspection to make sure you're not pouring over buried gas or electric lines.
How long before I can seal the patio?
Wait at least 28 days after pouring before sealing. Sealing protects the concrete from stains and water damage. Use a concrete sealer rated for outdoor patios and follow the product instructions. Reapply every 2 to 3 years depending on traffic and weather.