Do you need hardcore for concrete base?

The ground should be levelled and well compacted using a small garden roller or a lump hammer to provide a base for your concrete. A layer of hardcore of a minimum of 100mm is needed for a sub-base and should be well compacted.

Why do you need hardcore under concrete?

What is Hardcore Used for? A hardcore bed provides an essential part of a strong foundation for building work; when well-compacted it gives a base in which the builder can have confidence when infilling the upper layers. This is an invaluable commodity when it is necessary to raise the level of a floor.

Do you need a stone base for 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.

What do you put under a concrete base?

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.

Can you pour concrete without a gravel base?

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 TO: Lay a concrete base - perfect for a shed or extension

Can I pour concrete directly on dirt?

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

Can you pour a concrete slab on sand?

Pour concrete over a solid, well-drained base

of sand or gravel over clay and other poorly draining soils to provide even support.

How thick should a concrete base be?

In general, 6 inch (150mm) slab thickness is considered for residential and commercial buildings with reinforcement details as per design.

Can I pour concrete over gravel?

Cement mix might work in some cases over an existing gravel driveway. Laying a concrete driveway over an existing gravel one is possible, but it is not generally recommended. The kind of gravel that is intended to go under cement is typically a smaller grade than what is used for gravel driveways.

How do you prepare a concrete base?

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.

How much gravel do I need under concrete?

Determine the depth of the excavation. Let's say it's d = 2 yd . Multiply the area and depth of the excavation to obtain its volume in cubic yards: 18 * 2 = 36 yd³ . The volume of gravel required is equal to the volume of excavation.

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.

What is the point of hardcore?

'Hardcore' is the construction term used to denote 'engineered' infill material that is placed within the confines of a building foundation (after removal of any unsuitable ground layers) in order to support a ground-bearing floor slab (Figure 1).

Can I use old bricks as hardcore?

No as you would get uneven settlement.

Can I use ballast instead of hardcore?

Ballast is available in different types for different needs. 0-20mm ballast is perfect for sub-base and concrete foundations. 20mm screened ballast is versatile and can be used on driveways, footpaths, oversite fill as well as sub-bases. Raised ballast is reserved for backfill, driveways and binding hardcore.

What kind of gravel do you put under concrete?

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.

What type of gravel is used for concrete?

Gravels constitute the majority of coarse aggregate used in concrete with crushed stone making up most of the remainder. Natural gravel and sand are usually dug or dredged from a pit, river, lake, or seabed. Crushed aggregate is produced by crushing quarry rock, boulders, cobbles, or large-size gravel.

How thin can a concrete base be?

What is the minimum thickness for concrete? A: Concrete is typically applied at a thickness of 2 inches or more, but the thicker it is, the stronger the slab will be. Four inches is most common for a slab. The thinner applications would include drives, walkways, slabs and footers, just to name a few.

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.

How thick does concrete need to be to not crack?

To prevent load-stress cracking, make sure a slab is built over a uniformly compacted, well-drained subgrade, and is thick enough to withstand the kind of use it will get. In residential concrete, 4 inches is the minimum thickness for walkways and patios.

Is gravel or sand better 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.

Is sandy soil good base for concrete?

Sand does not take on water like clay and peat. This means that a concrete foundation constructed on sandy soil does not generally have an increased risk of cracking as a result of fluctuating water content in the surrounding ground. However, there is another potential problem with sand.

Can you pour concrete directly on sandy soil?

Failing to Prep the Site

If you're lucky enough to have sandy soil in your yard, you can simply remove the grass and topsoil and pour a layer of gravel for extra drainage. Make sure the surface is firm and level before you start pouring concrete as well.