Calculating how much concrete you need for stairs involves adding together the volumes of all the various stair parts.
How you build your stairs affects their volume and the amount of concrete you’ll need.
The average cost of concrete is between $110 and $150 per cubic yard.
Figuring out how much concrete you need for stairs isn't as complex as it may first seem. The trick is to calculate the volumes of the various stair parts and add them up at the end. Then do a little conversion based on the product you're using, and you're done.
The volume of your stairs is the crucial measurement when determining how much concrete you'll need for the project. Whether you're purchasing ready-mix concrete in bags, having it delivered in bulk, or making your own concrete, the calculations are the same.
You can purchase concrete, or the materials to make concrete, in ready-mix bags or cubic yards from a supplier or delivery company. The table below shows simple conversions from volume in cubic feet to cubic yards to concrete bags.
60-pound bag = 0.45 cubic feet
80-pound bag = 0.60 cubic feet
Volume in Cubic Feet | Cubic Yards of Concrete | Number of 60-Pound Bags | Number of 80-Pound Bags |
---|---|---|---|
3.375 | 0.125 | 8 | 6 |
6.75 | 0.25 | 15 | 12 |
13.5 | 0.5 | 30 | 23 |
27 | 1 | 60 | 45 |
To figure out how much concrete you need for stairs, you have to calculate the total volume of the stairs. Below, we take a more in-depth look at measuring, but the basic idea is that you’ll measure the height (also known as rise), depth (also known as run), and width and multiply the values together to get the volume in cubic feet for each stair. Then simply add the individual volumes together to get the total volume.
Cubic Feet of Concrete for One Stair = Height x Depth x Width
For the purposes of this article, we’re focusing on a solid staircase, meaning its entire volume requires concrete. (It’s also possible to build concrete stairs more like stairs with stringers. The stringer part is called the carriage and is where the rebar is located to provide necessary support.)
The easiest way to calculate the volume of a solid staircase is to simply divide the stairs into several rectangles, where each rectangle includes the space directly under each tread and the landing.
Multiply height (rise) by depth (run) by width to determine the volume of each section. Then add all of the values for your volume total.
While building a concrete staircase is an excellent way to boost your DIY skills, it's also a lot of hard work. Most homeowners opt to hire a concrete professional for this type of job. Hiring a local concrete contractor will ensure your pro knows the local building codes and will use a product that will hold up best in your climate.
The average cost of concrete for stairs or slabs is between $110 and $150 per cubic yard, or between roughly $4 and $5.50 per cubic foot for materials. Installation, form building, form materials, and preparation will increase the cost to between $150 and $200 or more per cubic yard.
Concrete hardens quickly. If you have extra at the end of your project, you can divide it into several small chunks that will be easier to manage for disposal. Concrete isn't hazardous waste, so you can dispose of it in a dumpster. However, you can check with your municipality to see if it offers recycling services for solid concrete.