Do you have to put sand under concrete?

As a general rule, stay away from using sand as a subbase. You're better off using gravel. Your concrete will last longer and have less of a chance of cracking over time.

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Do I need to put anything 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. Adding a layer of crushed stone will add proper drainage, as well as create a barrier between your slab and the ground.

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Why do you need to sand before concrete?

To prevent cracking and crumbling, concrete patios need to be built on solid, well-drained soil. If you live in a region with lots of clay in the soil, you will need to dig down further and backfill with layers of compacted sand and gravel.

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Is it OK to pour concrete on dirt?

Long story short, yes you can pour concrete over dirt. However, you need to follow the process outlined in this article for the best results. If this all seems a bit overwhelming, we suggest reaching out to a professional concrete contractor. Razorback Concrete is always willing to work with you.

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Can you pour concrete directly on grass?

Technically you can, but you really shouldn't pour concrete over grass. To maintain its tensile strength, concrete needs to be laid on a firm, even, and dry foundation. Grass and soil will naturally channel moisture into the concrete from below, which will likely result in it cracking over time.

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Do You Need Gravel Under Concrete?

20 related questions found

How do you prepare ground for concrete?

How to Level the Ground for a Concrete Slab
  1. Step 1: Remove Any Debris or Obstacles. ...
  2. Step 2: Mark the Area. ...
  3. Step 3: Excavate the Area. ...
  4. Step 4: Compact the Soil. ...
  5. Step 5: Add a Layer of Gravel. ...
  6. Step 6: Add a Layer of Sand. ...
  7. Step 7: Check for Level. ...
  8. Step 8: Place the Forms.

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What happens if you make concrete without sand?

In order to produce a strong, resilient concrete mix, you need to get the ratio of aggregate to sand to cement right. So if you don't mix sand to the cement, cement will set of course but will give a lot of shrinkage crack and may not give the desired bonding.

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What happens if you use cement without sand?

One can use pure cement, but it won't be as strong as concrete due to a lack of aggregates. The compressive strength of pure Portland cement typically does not exceed 3500 psi, even after 28 days of curing. Concrete, however, can exceed 10,000 psi with the proper additives.

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What is the best base for under concrete?

What Material is Used for a Slab Base? The base in concrete construction is usually a form of crushed stone. Most concrete contractors want a mix of coarse and fine aggregate to create a compactable base that is going to be safe for settlement and drainage.

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Is it better to put gravel or sand under concrete slab?

As a general rule, stay away from using sand as a subbase. You're better off using gravel. Your concrete will last longer and have less of a chance of cracking over time.

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Can you concrete without sand or gravel?

No, you cannot make concrete without gravel. The ingredient mix of 1 part cement, 2 parts sand, and 3 parts gravel (stone) is what makes up concrete. Without gravel, concrete would not be strong or be able to be used as a foundation or base that could withstand heavy loads.

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What do you put under concrete?

Instead, use a layer of gravel underneath your concrete slab. Because concrete is porous, it absorbs water. If you place concrete directly onto dirt, water will collect under the concrete and slowly erode the bottom of the pad. Gravel prevents this erosion by allowing water to drain away from the concrete.

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Can you just pour concrete?

You can pour concrete using items you have in the shed or garage; it does not have to take any special tools to do minor projects. Pouring concrete takes a little muscle as the mixture is quite heavy.

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What is concrete not good under?

Concrete has relatively high compressive strength, but significantly lower tensile strength. As a result, without compensating, concrete would almost always fail from tensile stresses (Stress (mechanics)#Mohr's circle) even when loaded in compression.

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Does concrete need to breathe?

An excess of moisture is the #1 contributor to floor system breakdowns. How does it happen? Well, as we mentioned above, concrete breathes. It may feel solid but it's actually porous, and riddled with capillaries.

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What is concrete without sand called?

No-Fines Concrete is a lightweight concrete made up of only coarse aggregate, cement and water by omitting fines (sand or fine aggregates) from normal concrete.

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What is an alternative to sand?

Crushed Dust or Quarry Dust

Crusher dust (quarry waste) is by product of stone crushers while producing coarse aggregate. Instead of disposing them in landfills, it can be best utilized as partial replacement to sand.

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Can you just mix cement on its own?

Cement is generally made from limestone, clay and sand. It's important to realise that you cannot use cement alone and it will need to be mixed with other materials to make a concrete or mortar mix. We stock a wide range of ready-made cements which can be used to make various concrete and mortar mixes.

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Why does concrete need sand and gravel?

Instead, aggregates are added to increase the volume and tailor the concrete to its final use. Typically, 60 to 80 percent of the concrete is aggregate. In most cases, the aggregates are sand and gravel. When sand is used alone, the result is mortar.

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Is cement on its own strong?

Cement is not stronger than concrete. On its own, in fact, cement is prone to cracking. When combined with aggregate materials and water and allowed to harden, however, cement—now concrete—is extraordinarily strong.

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Can I make concrete with crush and run?

Crusher run base material for roadways is very close to your thought process. If you add cement to this, you can develop a reasonably strong concrete, assuming you are not looking for strengths that are over about 4000 psi.

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Do I need plastic under my concrete slab?

You are not required to have a vapor or moisture retarding barrier for outside concrete pads or unheated buildings. Although a vapor or moisture retarder or barrier is not necessary beneath concrete floors used for unheated carports, driveways, and outbuildings, some DIY enthusiasts and builders recommend it.

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