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Dig the ground down to the proper depth. Smooth out the ground with the flat side of a rake so that you have a level surface. Tamp the ground with a hand tamper or mechanical tamper. Pour 2 inches of small, rounded gravel for additional drainage needs.
Can you pour concrete directly on dirt?
Long story short, yes you can pour concrete over dirt.
Do you need gravel under concrete?
Whether you pour concrete for a walkway or patio, a strong gravel base is required to prevent the concrete from cracking and shifting. Gravel is especially important in clay soil because it doesn’t drain well, which results in water pooling under the concrete slab and slowly eroding the soil as it finally drains.
How do I prepare an area for concrete?
How to Prepare Your Site and Soil Before Pouring Concrete Preparing the Soil for Concrete. Make a Stable Base for the Concrete. Prepare the Site for Pouring Concrete. Build up the Concrete Formwork. Dig & Smooth Out the Ground. Compact Each Layer of Concrete Base. Dampen the Base. Tamp the Base.
What is a good base for a concrete slab?
What is the Best Base for a Concrete Slab? Most people build a driveway or a patio so in that case, a good choice would be a mix of coarse and fine aggregate which will create a compactable base. Overall, a mix of crushed stone and stone dust is the best base material for any concrete flatwork.
What kind of gravel do you put under concrete?
Depending on what the driveway will be used for, the base may need to be 4 to 12 inches. Ideally, 6 inches of crushed stone or gravel should be used for most driveways. Proper application requires that the driveway hole be dug out, and the soil has to be prepared.
Can you pour concrete over gravel?
Laying a concrete driveway over an existing gravel one is possible, but it is not generally recommended. However, if the gravel in your driveway is small enough, it is possible to create a cement driveway over the existing one.
How do you crush concrete into gravel?
Strike the slab with a sledge hammer about 12 inches from the point where the pickax touches the underside of the slab. Do this repeatedly, and after a short time the slab will break up into small pieces.
How many inches of gravel do you need for a concrete slab?
You will need 3 inches of gravel under a concrete slab that is 4 inches thick. More gravel is better, but 3 inches is the minimum amount of gravel you should have with a 4” slab. Use ¾” washed and screened gravel, then compact it to level.
Can you use sand as a base for concrete?
Simply put, sand isn’t sturdy enough to work well as a subbase for something like a driveway. It is also difficult to maintain a level sand surface when pouring concrete, and therefore difficult to maintain a uniform thickness of the concrete slab.
Do you need rebar for 4 inch slab?
The thickness of rebar should be no more than 1/8 that of the slab, so a 4” slab shouldn’t have steel greater than #4 or 1/2″ bar. It’s best to check with a Structural Engineer if your slab will bridge or cantilever. What is this? For 4” concrete slabs used for driveways and patios, #3 rebar is common.
How much does it cost to pour a 24×24 slab of concrete?
A typical 24×24 garage slab costs between $3,057 and $5,944 with prices ranging from $5.31 to $8.31 per square foot for a 4” reinforced slab of concrete, and $6.83 to $10.32 per square foot for a 6” slab of reinforced concrete.
Can I use gravel as a sub-base?
If your builder uses the gravel he may find it will dissipate too easily into the ground and will spend more time and money to get the levels needed. I would not advise using the gravel. A well constructed base means your drive will never get sink holes.
Can I use concrete as a sub-base?
Any potential ‘soft-spots’ in the subgrade can allow the concrete to sink from the center or turn up from the edges. Owing to its inflexibility, the concrete slabs can crack. As concrete is highly compressed and heavy, it may crack under its own weight if not provided a suitable sub-base.
How many yards of concrete do I need for a 24×24 slab?
For example, for a concrete slab that is 24′ X 24′ X 4”, simply enter 4 in the Thickness/Depth field, 24 in the Width field, and 24 in the Length field. Click “Calculate”. Your answer should be 7.11 yards. Note: The Concrete Volume Calculator can also be used to determine yardage for aggregate products.
Should you put plastic under concrete driveway?
A concrete driveway will increase property values in most areas, that is, if it is done properly. Never place concrete directly on a polyethylene vapor barrier or bone-dry subgrade. The subgrade should be damp, with no standing water.
How many bags of cement do I need for 12×12?
of 40lb bag = 1.76 ÷ 0.011 = 160 bags. To determine how many bags of concrete you will need, divide the total cubic yards needed by the yields, at 5 inch thick, for a 12×12 slab you will need 2.22 yards of concrete, so number of 80lb bag of concrete = 2.22 ÷ 0.022 = 100 bags, No.
Can you put quikrete over gravel?
Evenly spread 3 to 4 inches of QUIKRETE All Purpose Gravel and then level the gravel. Compact the gravel base using a tamper. TIP: a solid sub-base will help prevent erosion and slab settling. Dampen the gravel base using a garden hose to prevent shrinkage cracking especially in hot temperatures.
What happens if you don’t put gravel under concrete?
Because concrete is a very porous material, it will absorb any moisture that it contacts. This can cause pooling. Without crushed stone, pooling water will settle under it and erode your slab.
Do you need a moisture barrier under concrete?
Although a vapor retarder or barrier isn’t required under slabs used for unheated garages and outbuildings, it is recommended. Moisture moving through a concrete slab into the building structure can cause dampness issues, and even cause metal sitting on the pad to corrode and stain the concrete.
How thick should driveway concrete be?
Placing concrete at the proper thickness Place concrete at a minimum thickness of 4 inches. Increasing the thickness from 4 inches to 5 inches will add approximately 20% to your concrete cost, but will also boost your driveway’s load-carrying capacity nearly 50% , according to the Tennessee Concrete Association.
