No contest. Chert isn’t even anything particular; it could be a wide variety of minerals with no composition guarantees.

What is the best base for concrete driveway?

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.

What base do you use for a driveway?





crushed gravel base

A good crushed gravel base beneath the blacktop is the secret to a long-lasting driveway. The base is the foundation for a durable driveway, making it critical to pick the right base material. Installing crushed, granular based gravel on a compacted subgrade is the best start to a strong base.

What is a good base for a gravel driveway?

The bottom layer should be comprised of stone (6” crushed rock) or consider 6” recycled concrete. The ideal thickness of each layer is between 4 to 6 inches. The middle layer should also be angular stones about 2” to 3” in diameter such as our #2 Bluestone.

What kind of gravel do I need for a concrete slab?

crushed stone





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.

What is the best base under concrete?

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.

How thick should the base be for a concrete driveway?

The minimum thickness in most codes for a residential driveway is 4-inches of concrete on a prepared base. Using stronger concrete can decrease that to 3” in some areas, although it won’t decrease the cost much if any. A properly prepared base and subbase will increase the driveway thickness by 4” to 8” too.

Do you need gravel under concrete driveway?

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.

What goes under 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.

What is the cheapest road base material?

Crushed concrete, sand and gravel mix, and crushed shells are the cheapest stones at $15 per yard.

Can I pour concrete directly on dirt?

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

How deep should a driveway base be?



Make sure the gravel layer is at least 50mm (5cm) deep and the gravel surface is spread across the surface. Simply rake over the entire area to help distribute the gravel evenly.

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.

Do you need plastic under concrete driveway?

The American Concrete Institute (ACI) recommends a minimum of 10-mil polyethylene or thicker for vapor retarders under concrete. Their Guide to Concrete Floor and Slab Construction ACI 302.1R-15 identifies that thicker poly provides a better barrier and is also more puncture resistant.

Can you 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.

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

Excavate the soil to a depth of 8 inches, allowing 4 inches for the gravel base and 4 inches for the concrete slab.

Should you put plastic under concrete?

Quote from the video:
Quote from Youtube video: But you want to have a six mil plastic. That's code to put down over the slab or I should say the dirt. Before you pour your slab. The reason that is is moisture migrates from the dirt up.

Do you need rebar for 4 inch slab?

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. The thicker the slab, the more durable it will be.

Can I use chicken wire to reinforce concrete?



Chicken wire or wire mesh can be safely used as a reinforcement in concrete when the concrete is not used in structural or high-weight areas. The wire mesh or chicken wire can add stretching strength that concrete does not have, giving the concrete rigidity when facing specific pressures.

Does a concrete driveway need wire mesh?

When it comes to concrete, you can’t avoid cracks entirely, but wire mesh reinforcement will help hold the material together when they do occur. Also, it will help evenly distribute the weight of cars on your driveway. The added strength of steel is especially crucial if your subgrade isn’t up to par.