You may give little thought to the concrete around your home, but there are many advantages of concrete, from its ability to create a solid surface to binding things together. The ingredients for DIY concrete are widely available, and buying them in bulk to make your own mix is more cost-effective than premade options. Follow this guide to understand all the ins and outs of how to mix concrete, from exactly which materials you’ll need and in what ratio to use them.
Prepping to Make Concrete
There are a couple of things to do before whipping up this recipe for concrete, like finding out exactly how much of each material you’ll need and in what ratio to combine them.
What Is Concrete Made Of?
Almost all types of concrete are made from the same basic ingredients: sand, stones, Portland cement, and water. It's easy to mix up the terms concrete and cement since cement is a major ingredient—and because the words are often used interchangeably.
The ratio in which you use these ingredients will determine the strength of your concrete. For example, using sand, stones, and Portland cement in a ratio of 1-to-2-to-3 will give your cement a strength of 3,000 pounds per square inch (that’s the amount of weight it can handle before cracking or collapsing). This standard works for most residential purposes, but you can adjust the strength per square inch by increasing the amount of stone aggregate and Portland cement while maintaining the amount of sand.
You can also determine the water concentration by investigating the right concrete slump for your project. Concrete slump measures how much the mixture falls—slumps, essentially—when placed in a set mold and then released to settle. You can purchase a concrete slump kit at your hardware store.
Take Measurements to Make Sure You Have Enough Supplies
There’s nothing worse than realizing you don’t have enough supplies after you’ve already started mixing your own concrete. That’s why it’s important to take meticulous measurements before you begin.
Start by measuring the area of the project. Determine how long and wide it is, then multiply those two numbers to get the square feet. Then, measure the depth of the project, and multiply that by the square feet to find out how many cubic feet of concrete you will need. Make sure your depth is in feet and not inches.
For example, a 4-foot-by-4-foot-by-4-inch-thick concrete pad would require the conversion of the 4-inch thickness to feet (.33 feet). Each cubic foot of space requires roughly 130 pounds of dry concrete mix. Multiply the amount of cubic feet by 130 to arrive at the total weight of concrete mix that you will need.