Concrete flatwork refers to any poured surface, such as patios, sidewalks, foundations, and driveways, and is poured to move in a horizontal plane. It is then formed with a frame and sub-base material, typically made of either rebar or another aggregate rock. This strengthens and prevents cracks and damages to the concrete surface.
Can you Pour Concrete Flatwork Directly on Dirt?
We do not recommend pouring concrete directly on the dirt. Dirt is a soft and porous surface, which does not support the concrete. Without a proper base, you risk warping, sinking, and cracks in your concrete. The preferred and recommended method to lay concrete on dirt is to first add four inches of clay slab, then a layer of gravel or sand. We want to avoid any cracks and voids that could be created underneath which could ultimately cause unsupported areas to crack under heavyweights, such as cars and trucks.
What size Rebar Should I Use for a 4-inch Slab?
For rebar in patios, driveways, basement floors, and foundations, be sure to use rebar between three and six. We encourage you to use the one-eighth rule to measure rebar in anything else. For example, the size of the rebar should be ⅛ the thickness of the slab.
Is Gravel Necessary under Concrete, and What Type of Gravel Works Best?
Concrete is strong. That said, improperly prepared flatwork concrete will not hold up to years and years of elements, pressure, and unexpected problems like tree roots. If your concrete isn’t properly prepared, or poured with a layer of strong subgrade, it will ultimately crack under pressure. Sand, gravel, and crushed stone are among some of the options for a durable subgrade. In many cases in Chester County, we recommend crushed stone for the best results. While it can tend to run on the pricier end of the cost spectrum, it is by far your best investment. If you want your concrete to go as long as your dollar, go with crushed stone. Here are a few reasons we stand so firmly on this opinion:
- Crushed Stone Creates a More Even Surface: Concrete flatwork alone poses a wealth of risks. After a few years, it can erode, crack, and sink if the foundation is not properly prepared. These problems might not seem like a big deal while planning your project, but what often ends up happening is that your concrete will need to be replaced, quickly. Roots of plants can also work their way under concrete, which can cause cracking. Another problem is water trapped beneath your concrete. This can create pooling, mud, and mold in places where mud and mold should not be. To prevent this, add a layer of crushed stone as protection. It solves the dilemma of cracking and sinking in your concrete by serving as the first line of defense against underground shifting and pressure. It will also prevent mold, mud, and pooling by putting a layer between the ground and the concrete.
- Drainage: Concrete flatwork happens to be a very porous surface, which comes in handy when forming. However, this porous aspect to concrete means that it will absorb any moisture below it and lock it in. This creates pooling, which creates erosion, which creates cracking and sinking. We also recommend an additional vapor barrier between the layer of subgrade and the concrete itself for added protection.
- Settlement Crack Concerns: After a long enough time, concrete will crack and create unevenness in the sidewalk or surface. This happens at any time the ground below the concrete shifts, which can be a result of compacted soil. To combat this, that extra layer of subgrade will do the trick and leave you satisfied with the finished product.
How much does Concrete Flatwork Usually Cost Per Yard?
A slab of concrete typically costs between $4 and $8 per square foot. Of course, there are many factors in our custom project proposals, and we take the time to review them with you before you agree to sign our contracts. We always try to deliver the best results for your money.
How can Morrison Concrete help with your Concrete Flatwork Needs?
Morrison Custom Concrete is proud to have the expertise and experience in laying flatwork concrete. We will inspect your project and provide you with the proper guidance, including where we can help you save money, before starting the job. You will be thrilled with the finished result!