How deep should a concrete base be?

For small residential buildings that are ground level or at least 1 1/2 times the width of footing, the minimum depth is around 5 feet. In colder climates, the depth of foundations is a minimum of 1 1/2 meters below the surface due to frost.
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How thick should a concrete base be?

As a rule of thumb, concrete slabs supporting lighter weights such as paths, patios and shed bases will need to be 75-100mm thick, while driveways and garages need to be at least 100mm thick. Slabs intended for commercial use should be at least 175mm thick and reinforced.
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How thick does a concrete base need to be for a shed?

A 4-inch slab is generally a good thickness for a typical shed. This concrete floor can be poured in most locales on a 4-inch base of compacted gravel. That requires an excavation of at least 6 inches to make a slab that will be 2 inches above the surrounding ground.
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How deep should a concrete slab base be?

A Good Base Is Everything!

Bringing in 4 to 6-in. of a good compact-able base is a good rule of thumb, but the exact amount of base a concrete driveway needs depends on the condition of the existing soil, the climate, and what you plan to park on your driveway.
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How much of a base do you need for concrete?

Deciding the correct amount of walkway base material is actually quite simple. For sidewalks and patios or any other light duty areas you will only need a 4 inch base of 3/4 inch quarry process or RCA beneath a 1 inch layer of concrete sand.
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Concrete basics for Beginners from top to bottom, ground prep, rebar, sealing



Can I pour concrete directly on dirt?

Long story short, yes you can pour concrete over dirt.
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Do you need gravel under concrete?

You do need gravel under a concrete slab, footing, or patio. Gravel provides a solid foundation for your concrete as it can be compacted. It also improves drainage, preventing water from pooling beneath the concrete.
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Is 3 inches of concrete enough?

A concrete patio slab should be at least 4 inches thick and have a compressive strength of 3,000 PSI. You're free to make it thicker or stronger, but unless specifically required for your patio build, it's likely overkill to surpass 4 inches in thickness.
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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. 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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What is the best sub base for concrete?

The best sub-base for a concrete slab is gravel. The soil has to be prepped first before the gravel can be laid down; pouring concrete directly onto rock is not considered a best practice. You can use different kinds of gravel for the subbase as long as it is clean and uniform in shape and size.
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How deep does a concrete base need to be for a garden room?

If the base is to go on soft ground or lawn it needs to be dug out following the string lines. To make the base level with the ground surface the hole needs to be 6” or 150mm deep. This is because 3” or 75mm depth of concrete is recommended and this should lay on a 3” or 75mm bed of compacted hardcore.
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Do you need a sub base for concrete shed base?

Whilst not technically required, a subbase layer will provide your concrete shed base with a highly durable surface on which to sit, that won't collapse under the weight of your shed whilst also providing excellent drainage qualities. Once you add the subbase material, it will need to be compacted.
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Is sand a good base for 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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How thick should a concrete base be for a patio?

Four inches is the minimum thickness for a concrete patio. You'll want to make it six to eight inches thick if the patio will support a structure such as a gazebo or hot tub.
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What is the thinnest you can pour concrete?

Pouring Too Thin

Be sure you never make your slab thinner than four inches for any application. Six inches is the minimum thickness for a concrete slab that may see any kind of heavy vehicle traffic.
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Can I pour a 2 inch concrete slab?

Pouring concrete over concrete requires a minimum thickness of 1.5 inches. In most circumstances, I prefer not to pour fresh concrete that is less than 2 inches thick. Two inches of bonded concrete (or more) provides appropriate strength for a wear surface, especially if driving over it.
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How do you prepare ground for concrete?

  1. Dig the ground down to the proper depth. ...
  2. Smooth out the ground with the flat side of a rake so that you have a level surface. ...
  3. Tamp the ground with a hand tamper or mechanical tamper. ...
  4. Pour 2 inches of small, rounded gravel for additional drainage needs.
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Can you pour concrete over grass?

Cheap and versatile and easy to pour, concrete will last you years down the road. You can pour it just about everywhere—including on the grass. Although it takes a little work, pour concrete over grass to create that walkway you always wanted or that mowing preventative you could previously only dream about.
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Do you need rebar for 3 inch slab?

Rebar is not necessary for every concrete project. The general rule of thumb is that if you are pouring concrete that is more than 5 inches in depth, you are probably going to want to add in some rebar to help reinforce the entire structure.
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What is the minimum thickness of a concrete floor on ground?

4.3. Thickness. 1) Concrete slabs shall not be less than 75 mm thick exclusive of concrete topping.
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How much weight can 4 inches of concrete support?

A 4-inch thick concrete can support upto 40 pounds of weight. Weight should not exceed 40 lbs/sq ft on an undetermined 4-inch slab. 80 lb/sq ft in isolated areas is fine, but unless you know what the soil bearing and reinforcing is for that slab, you might be looking at cracking.
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Does a 4 inch slab need rebar?

No, rebar is not required for a 4-inch slab of concrete on grade. A 4-inch-thick slab cast on the ground and in constant touch with it will float, with no need for rebar. For concrete that is 5–6 inches thick, rebar is suggested.
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Can you pour concrete over rocks?

Big rocks are not a problem as long as there is uniform concrete coverage and adequate rebar for temperature fluctuations. If the big rocks protrude up above grade and if you have a few in a row, it will weaken the slab. We like things uniform, including the grade, thickness of the concrete, etc.
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How deep should footings be?

Depth of Footings

Footings should extend to a minimum depth of 12 inches below previously undisturbed soil. Footings also must extend at least 12 inches below the frost line (the depth to which the ground freezes in winter) or must be frost-protected.
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