What Size Gravel is Best for Driveways? (Guide)

What Size Gravel is Best for Driveways

When driveways are constructed using the right type of gravel along with being correctly installed and maintained, they can add charm to a home’s appearance.  The question is what size gravel is best for a driveway?

The type and size of gravel are critical to how well it forms a solid surface.

How Gravel is Used to Make a Driveway

 A gravel driveway is composed of several layers of different sizes of gravel. 

As a layer is put down, it is set with a mechanical tamper before another level is put down. 

The different levels of gravel serve different purposes such as providing drainage, strength, and degree of compaction.

Layers of a Gravel Driveway

These layers of a gravel driveway are done using angular gravel but you can use any you choose; this below gives you an idea of the size of gravel for each layer.

Base layer using larger gravel:  For this layer, you should use #1 angular gravel.  It approximately the size of a baseball; four inches in diameter.  You do not want to use round gravel because it does not bind together. 

Under the weight of the vehicles on the driveway, the round gravel will move easily.  With angular gravel, it is produced by a rock-crushing machine just for construction purposes.

This gravel will have many flat surfaces on each piece.  They will interlock and help to create a more durable driveway.

Middle layer using medium size gravel:  This layer is #4 angular gravel; about the size of a golf ball. 

You will need to place a four-inch layer of this gravel on top of the other layer of gravel.  This smaller gravel will fit well between and against the foundation of larger gravel. 

This will help to form a more solid base for the driveway.

Top layer using smaller gravel:  This layer is #57 angular gravel; it is about the size of a nickel.  Since this gravel is smaller than the middle gravel it will also seat well between and against both the larger gravels.  This size contains rock dust. 

It will cause pieces of gravel to adhere to each other better.

How Much Gravel Will you Need?

Before purchasing gravel for your driveway there are some things that you need to consider.

Size of the stone:  All driveway gravel is not the same, from the base to the top level. 

The first thing to consider is the surface stone, which is the one that you choose for aesthetic value.  The larger the stone the less you will need. 

To help determine the price, you also have to take into consideration the weight, size, rarity, and other factors.

Size of base material: For your driveway to be stable, you will need to use large crush stone; a layer three to four inches thick followed by a smaller stone three to four inches thick and then the top layer three to four inches thick.

Project size:  This is the first thing that you should look at to determine the gravel you will need. 

For example, for a standard rectangular driveway, you multiply the length by the width by the depth of the driveway to figure out the volume of stone.  Remember that you will need three to four layers of each stone.

Popular Gravel Choices

In addition to angular gravel, there are three other choices that some use for a top layer on their gravel driveways.

River rock:  This refers to a diverse group of rocks.  They have been rounded and worn by the action of moving water.  They come in a variety of colors, textures, and sizes. 

They will give your driveway a natural look but if the driveway has inclines, steep slopes, or curves, use caution choosing these rocks.  The reason is that the smoothed rocks can significantly shift under vehicles. 

The price for river rock varies, depending on the season, availability, and area you live in.

Pea gravel:  This gravel is generally three-eighths of an inch and soft to the touch.  This is to its smooth and rounded sides.  They are naturally weathered and comes in a variety of colors, including neutral like gray or brown. 

It is generally multicolored in appearance.  It has the same natural, attractive look as river rock.  The one difference between pea gravel and river rock is that pea gravel does not have the vehicle instability like river rock. 

Because they are round they do not interlock like crushed stone usually does.  This seems to be a better drain rock than quarry.  The reason is that it will allow water to flow between the round rocks.

Dense grade:  This is also referred to as quarry stone.  It is a dense grade crusher run, road stone, and aggregate. 

It is a combination of stone dust and crushes stone that is three-fourth inch or less.

The stone is designed to bind together and form a solid strong surface when it is compacted.  It is not good drainage gravel for wet climate driveways.  How much it costs will depend on the availability, proximity of a quarry, and the market.

Conclusion

  • To help prevent weed infestation in your gravel driveway, lay landscape fabric after you dig the foundation and before you put in the first layer of gravel.
  • This driveway is more practical for flat land with no appreciable gradient because when these types of driveways are built on a slope, they may erode because of rainwater. 
  • For maximum adhesion, specify uncleaned gravel so it will bind the gravel into a solid surface.
  • As necessary, you can top off the driveway with the smaller gravel, #57 angular gravel.
  • To help keep the gravel in the driveway, you can place edging along the sides of the driveway by using bricks or large stones.
  • When choosing stone or rocks for your driveway, opt for crushed, man-made rock gravel.  The reason is that these pieces will bind well together, thus increasing stability. 
  • When choosing the gravel for your driveway base your choice on how well it drains, cost, appearance, and price.

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