Laying concrete yourself takes five to seven days of actual work spread over two to three weeks, depending on weather and curing time
A concrete patio is poured in layers: the ground is leveled and compacted, a gravel base goes down, wooden forms are set to the height you want, concrete is mixed and spread, then smoothed and finished. The whole job for a 12-by-16-foot patio takes one to three people and costs between $300 and $800 in materials if you mix and pour yourself. The longest part is waiting for the concrete to cure—you cannot walk on it for three days and should not use it fully for a week.
The work itself is physical but straightforward. You dig, level, build a frame, pour, and smooth. The main things that go wrong are uneven ground (which makes the patio slope the wrong way), forms that shift during the pour (which makes edges wavy), and concrete that cracks because it dried too fast or the base was not solid. All three are preventable if you follow the steps in order and do not rush the base.
Key Takeaways
- The ground must be level and compacted solid before anything else happens, or the patio will crack and settle unevenly.
- A four-inch gravel base under the concrete prevents water from pooling underneath and causing frost heave in winter.
- Wooden forms must be staked firmly and checked for level in both directions, because any shift during the pour ruins the finished surface.
- Concrete cures slowly—it is walkable after three days but should not bear weight or furniture for a full week.
- Finishing the surface (broom finish for grip, trowel finish for smoothness) happens while the concrete is still wet, so you have a narrow window to get it right.
Prepare and level the ground
Mark out the patio area with chalk or spray paint. Measure the corners with a tape measure to make sure they are square—measure diagonally from corner to corner; if both diagonals are the same length, the corners are square. Remove grass, roots, and topsoil from the marked area down to bare earth. A shovel works for small patios; a sod cutter (rented from a tool rental shop for $40 to $60 per day) is faster for anything larger than 10 by 10 feet.
Dig out any soft spots or low areas. The ground should be firm—if you step on it and sink more than a quarter inch, it is too soft. Compact the soil with a hand tamper (a flat metal plate on a handle, $30 to $50 to buy) or a plate compactor (rented for $50 to $80 per day). Make multiple passes over the entire area, overlapping each pass. The goal is a surface that does not move when you walk on it.
Check the level with a four-foot level or a longer straightedge and level. Lay the straightedge across the area in several directions and look for gaps under it. Fill low spots with soil, compact again, and recheck. This step takes time but saves you from a patio that pools water or slopes the wrong way.
Add gravel base and set wooden forms
Spread four inches of gravel (crushed stone, not pea gravel) over the compacted ground. Spread it evenly and compact it the same way you compacted the soil. This layer lets water drain away from under the concrete instead of pooling there, which prevents frost heave in cold climates and keeps the concrete from cracking.
Build a frame from two-by-four lumber around the perimeter of the patio. Cut the boards to length and lay them on edge on top of the gravel. Drive wooden stakes (cut from two-by-four scraps, about 18 inches long) into the ground on the outside of the frame, one stake every three to four feet. Nail or screw the frame to the stakes. The top of the frame should be level in one direction and slope slightly (about one-eighth inch per foot) in the other direction so water runs off. Use your level to check this as you go.
The frame is your guide for the concrete depth and surface. If it shifts during the pour, the concrete surface will be uneven. Stake it firmly and double-check the level before you start mixing concrete.
Mix and pour the concrete
Concrete comes as bags of dry mix (you add water) or as ready-mix delivered by truck. Bags are cheaper for small patios (under 50 square feet) but require hand mixing or a mixer rental. Ready-mix is easier for larger patios but costs more and requires the truck to reach your site. For a 12-by-16-foot patio (192 square feet), you need about 2.4 cubic yards of concrete, which is roughly 65 bags or one ready-mix truck load.
If you use bags, mix them in a wheelbarrow or mixer according to the package directions. The concrete should be thick enough to hold a shape but wet enough to spread—think of thick pancake batter. If it is too dry, it will not fill the forms; if it is too wet, it will sag and crack as it dries.
Pour the concrete into the frame, starting at one end and working toward the other. Spread it with a shovel so it fills the corners and reaches the top of the frame. Tap the sides of the frame with a rubber mallet to help the concrete settle and release air bubbles. Work in sections if the patio is large, pouring and spreading one section before moving to the next.
Strike off and smooth the surface
Once the concrete fills the frame, use a straightedge (a long board, a two-by-four, or a metal screed board) to strike off the excess. Lay the straightedge across the top of the frame and drag it toward you in a sawing motion, letting the excess concrete fall off the sides. Make multiple passes until the surface is level with the frame and smooth.
Let the concrete sit for 10 to 30 minutes. The surface will firm up slightly. Then smooth it with a float—a flat metal or wood tool that you push across the surface in overlapping strokes. This fills small holes and creates an even finish. A wood float leaves a slightly rougher surface; a metal float leaves it smoother.
If you want a broom finish (textured for grip), drag a stiff broom across the surface while it is still damp but firm enough that the broom does not sink in. If you want a smooth trowel finish, keep floating until the surface is as smooth as you want it. The window for finishing is narrow—usually 30 minutes to two hours after pouring, depending on temperature and humidity. Work quickly and do not overwork the surface, or it will become weak.
Cure the concrete and remove forms
Cover the patio with plastic sheeting or burlap to slow drying. Concrete that dries too fast cracks. Mist it lightly with water once or twice a day for the first three days if the weather is hot or dry. Do not let it dry out completely, but do not flood it either.
After three days, the concrete is hard enough to walk on carefully. After seven days, it has reached about 70 percent of its final strength and can bear normal use. After 28 days, it reaches full strength. Remove the wooden forms after three days by pulling out the stakes and prying the boards away from the concrete.
If you live in a cold climate, do not use salt on the concrete for the first winter—salt can damage concrete that is less than a year old. Use sand for grip instead.
Common mistakes and how to avoid them
Uneven ground is the most common problem. Skipping or rushing the leveling step means the patio will settle unevenly, crack, or pool water. Spend time on this step and check your work with a level in multiple directions.
Forms that shift during the pour create wavy edges and an uneven surface. Stake the frame firmly and check the level again just before you pour. If the frame moves, stop pouring, fix it, and continue.
Concrete that cracks as it dries usually means it dried too fast (cover it and mist it) or the base was not solid (compact the soil and gravel thoroughly). Cracks that appear after a week or two often mean water is pooling under the concrete because the ground was not level or the gravel base was not thick enough.
Finishing the surface too late or too early ruins it. If you wait too long, the concrete is too hard to smooth. If you start too early, your tools sink in and leave marks. Watch the concrete as it sets and start finishing when the surface is firm enough that your footprint does not sink more than a quarter inch.
Tools and materials you will need
| Item | Purpose | Buy or Rent |
|---|---|---|
| Shovel | Dig and spread soil and gravel | Buy ($20–$40) |
| Hand tamper or plate compactor | Compact soil and gravel | Buy tamper ($30–$50) or rent compactor ($50–$80/day) |
| Four-foot level or straightedge | Check ground and frame for level | Buy ($15–$40) |
| Two-by-four lumber and stakes | Build frame | Buy ($1–$3 per foot) |
| Gravel (crushed stone) | Base layer under concrete | Buy by the ton ($20–$50/ton) |
| Concrete (bags or ready-mix) | Patio surface | Buy bags ($4–$6 each) or order ready-mix ($150–$200/load) |
| Wheelbarrow or mixer | Mix concrete (if using bags) | Buy wheelbarrow ($50–$100) or rent mixer ($40–$60/day) |
| Straightedge or screed board | Strike off excess concrete | Buy ($20–$50) or use a two-by-four |
| Float (wood or metal) | Smooth surface | Buy ($15–$40) |
| Broom (stiff bristles) | Create broom finish | Buy ($10–$20) |
| Plastic sheeting or burlap | Cover concrete while curing | Buy ($10–$30) |
Frequently Asked Questions
How thick should a concrete patio be?
Four inches is standard for a patio that will hold foot traffic and light furniture. If you plan to park a car on it or use it for a hot tub, pour six inches instead. Thickness is measured from the top of the gravel base to the finished surface.
Can I pour concrete in cold weather?
Concrete cures slowly in cold weather and can be damaged by freezing before it sets. Do not pour if the temperature is below 50 degrees Fahrenheit or will drop below 40 degrees within 24 hours. Spring and fall are ideal; summer heat can make concrete cure too fast and crack.
What slope should the patio have?
Slope it about one-eighth inch per foot in one direction so water runs off instead of pooling. For a 12-foot-wide patio, that is about 1.5 inches of drop from one side to the other—barely noticeable to walk on but enough to shed water.
Do I need to seal the concrete after it cures?
Sealing is optional but extends the life of the patio, especially in cold climates where salt and freeze-thaw cycles damage concrete. Wait at least 28 days after pouring before sealing. Sealer costs $50 to $150 and lasts two to three years.
What if the concrete cracks after I finish it?
Small hairline cracks (less than one-eighth inch wide) are normal and do not affect the patio's strength. Larger cracks or cracks that grow over time usually mean the base was not solid or water is pooling underneath. Fill them with concrete crack filler ($10 to $20 per tube) or have a concrete contractor assess whether the base needs repair.