What Do You Put Under A Concrete Slab?

Can I use pea gravel under concrete?

If you use pea gravel beneath a patio, take a few simple steps to ensure the stability of the base before setting your surface stones, pavers or bricks.

Click to see full answer.

It should be ok to pour concrete over your gravel walk although you might want to give the concrete a little more depth along the sides..

Can you pour concrete directly on dirt?

Long story short, yes you can pour concrete over dirt.

Should you put plastic under concrete?

A concrete vapor barrier is any material that prevents moisture from entering a concrete slab. Vapor barriers are used because while fresh concrete is poured wet, it’s not supposed to stay that way. It needs to dry and then stay dry to avoid flooring problems. … This is why a vapor barrier under concrete is essential.

How many inches of gravel do you need for a concrete slab?

4 inchesA hand tamper is sufficient for packing gravel, but a plate compactor makes the job much easier, especially when preparing a large area such as a patio. Excavate the soil to a depth of 8 inches, allowing 4 inches for the gravel base and 4 inches for the concrete slab.

Is sand a good base for concrete?

Pour concrete over a solid, well-drained base of sand or gravel over clay and other poorly draining soils to provide even support.

How deep do you have to dig to pour concrete?

3 to 5 inchesThe ground should be dug to a depth of 3 to 5 inches with a trench dug on either side. If the ground is mostly clay, an additional 2 inches of depth is needed to hold gravel, which will aid in drainage. If the surface is prepared with a fluctuation in depth of no more than 1 inch, your concrete will be level.

How do you prepare the ground for a concrete slab?

Preparation is the most important aspect of pouring a concrete slab.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.

What is the best fill under concrete?

The top 6 to 12 inches of the backfill under the slab should be filled and compacted with well-graded gravel or crushed material. “Walls are typically backfilled with the removed earth or with a granular, open-graded material,” says Tull.

Do you need rebar for 4 inch slab?

No, you do not need rebar for a 4-inch slab of concrete on grade. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required. Rebar is recommended on concrete measuring 5 – 6 inches thick.

Is Clay a good base for concrete?

The clay can compress under the weight of the concrete, causing the slab to shift or sink over time. It also can leach moisture from the concrete itself, resulting in uneven curing and a brittle base. With proper preparation, however, it’s possible to pour a slab on clay soil without encountering these problems.

Do you pour concrete before or after pole barn?

New member. The only way to build a pole shed that will last and look good forever is to pour the floor first. The treat post rot out in about 10-15 years if they are in the ground. pour the walls put the post on the cement floor and it will last forever.

What is better for concrete patio rebar or mesh?

wire mesh, the short answer is: use both! … Concrete driveways that need to carry a heavy load should have both rebar and wire mesh to reinforce the concrete. For a patio, you might be able to get away with using welded wire mesh. But remember, all concrete will crack and all concrete will shrink.

What is the best base for concrete slab?

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. Crusher run (a mix of crushed stone and stone dust) is one of the best base materials for concrete flatwork.

Do I need gravel under my concrete slab?

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.

How thick should concrete be for a garage floor?

four-inchesThe concrete slab should be four-inches thick at least; it needs to be thicker if heavy equipment will rest on it. Building codes offer requirements for the concrete mix, which vary by region. The standards are expressed in terms of “compressive strength,” which boils down to the amount of water used in the mix.

How thick does a concrete shed base need to be?

The concrete base should be at least 75mm thick, with a similar layer of sub base, so you will need to excavate to the required depth and ensure that all plants, stones and debris are removed before compacting the ground with a roller or tamper.

Is it cheaper to mix your own concrete?

One of the least expensive ways to get concrete is to mix your own. You can buy bags of the mix from a home improvement store. Typically, you only have to add water for it to be ready to pour. … Otherwise, you risk getting a weaker concrete once it cures, which could lead to cracks or crumbles within a couple of years.