Concrete is affordable, durable, low maintenance, and more popular than ever, thanks to many modern industrial design trends. Knowing how to pour concrete, which doesn't require many special or expensive tools, can save you money on home improvement projects like a patio, walkway, driveway, or steps.
Just make sure to research thoroughly before beginning, consult with a professional, and aim for best practices to ensure your hard(scaping) work culminates in a safe and professional-looking product.
What you'll require will differ depending on the project you're tackling, but for a patio, items include:
Once you've selected a spot where the ground is even, measure the dimensions. Excavate and clear any obstacles until you reach raw earth—old concrete must go too. You'll need to dig about eight inches deep for a ground-level patio.
Check local codes so you know how to slope the structure for any run-off. One inch for ten feet is a good start.
You need to lay an approximately four-inch foundation for your concrete. This sub-base often comprises gravel, open-grade stone, or more compactable and expensive fine-grade stone, and the material you go for makes a slight difference in drainage.
The sub-base can't lie on unstable soil—compact the soil before laying it and compacting it with the hand tamper. A plate compactor may be more practical for larger projects.
Use heavy wooden planks for a wooden perimeter, and secure them with nails and screws. These planks will come in direct contact with wet cement, so they have to be solid. You can coat them with vegetable oil to make life easier later on in the process.
Your form's corners must be at right angles for square and rectangular structures. Measure and adjust if necessary.
Wire mesh prevents large cracks and provides support if the concrete will bear heavy loads. Six-inch squares of 10-gauge metal should do the trick, and these go on the inside of the form. Rebar doesn't do much for cracks but offers a superior load-bearing ability to mesh.
Now it's time for your concrete. You'll have to hire an industrial mixer for a bigger space, but if you're working in a small area, you can hand mix the concrete according to the instructions, using a wheelbarrow and shovel. Less is more when it comes to adding water to your 1:2:4 ratio of cement, sand, and gravel. When mixing, dress appropriately in long clothing, safety goggles, a mask, and gloves.
Concrete meets painstakingly prepared dig site mold during this step. Pour the concrete and use a shovel or concrete rake to push it to the corners and fill any low sections. Assistants come in handy here, both for tipping the wheelbarrows and helping to spread it out.
When it's spread out, start at the high point and run a wooden plank in a side-to-side motion along the surface to flatten and even the concrete out. Work fast and go in with the bull float to compact the screeded surface. You can use a hand float if water rises to the top, or wait for the liquid to dry.
You can choose to use a plank or other tool to make measured joints or cuts in the concrete to prevent cracks. Use your broom or trowel to make shallow patterns that will lead to a less slippery concrete surface. If you can't do this easily because of clumps on the broom, smooth the surface and wait for the concrete to set a little more.
This setting or drying step is called curing and takes up to three days. A tarp protects your efforts, and many experts recommend sealing your concrete as well, just after it's poured. When the concrete is cured, you can slide the forms out. The concrete will take about a month to fully cure.
Concrete is made up of a paste and an aggregate. Different types of concrete depend on various material ratios and what goes into these components.
Regular concrete is okay for pavements but doesn't have high tensile strength. High-density concrete is used in nuclear plants, lightweight concrete is suitable for roofs, and precast concrete is molded offsite for columns, staircases, etc.
There's also glass-reinforced concrete for exterior cladding panels, air-entrained concrete that allows for freezing, self-compacting concrete, polymer concrete, and prestressed concrete.
You must work at the correct temperatures to ensure your concrete cures optimally. Concrete mixtures contain water, which is quickly affected by temperature—if the environment is too hot or cold, you're not going to get the results you desire in terms of shape and strength.
It's best to pour concrete between 50°F and 60°F to maintain structural integrity. Be mindful of nighttime temperatures and a rainy forecast. In warmer weather, you can pour concrete at slightly higher temperatures, but after waiting at least four hours, you'll need to lightly spray the hardened concrete with water to make up for evaporation. You can do this up to ten times daily during the first 72 hours.
Pouring concrete can be a DIY task, but don't underestimate its difficulty. It's labor-intensive because the fluid mixture is heavy, and you'll likely need someone to give you a hand. Check local building regulations because you might require a permit, and confirm that you won't compromise water or septic pipes underground before digging.
If you can dedicate the time to prep work and approach the process methodically and with focus, you should be satisfied with the "after" pictures.