What Is #4 Rock, and What Are Some Good Uses for It?
If you’ve spent any time researching gravel or aggregate materials, you’ve probably come across terms like “#57 stone” or “#4 rock.” But what exactly is #4 rock, and when should you use it?
What Is #4 Rock?
The name “#4 rock” refers to a specific size of crushed stone or gravel. It typically consists of stones about 1.5 to 2.5 inches in diameter—larger than #57 stone, but smaller than riprap. Depending on the source, it can be made from limestone, granite, or other types of crushed rock, and it’s often used as a base material in construction and landscaping.
The geography of the Birmingham, AL area features significant deposits of limestone and granite, making it easy to source this type of stone locally, making it a cost-effective option for projects across Jefferson and Shelby counties.
Best Uses for #4 Rock
So, when is #4 rock the right choice? Here are a few of its top uses:
1. Construction Base
Because of its larger size and stability, #4 rock is often used as a sub-base layer beneath roads, driveways, and concrete slabs. It helps distribute weight evenly and prevents shifting over time, especially important in Alabama’s clay-heavy soil.
2. Drainage & Erosion Control
Need better water flow around your property? #4 rock allows water to pass through easily, making it a solid choice for French drains, culverts, and erosion control along slopes or drainage ditches. Birmingham’s hilly terrain and frequent rainstorms — especially during the summer months — make erosion control an important concern for homeowners and contractors alike.
3. Heavy-Duty Driveways or Parking Pads
If you’re installing a driveway that will see heavy vehicle traffic—think RVs, trailers, or construction equipment—#4 rock can provide the strength and durability you need beneath finer gravel layers, versus its smaller but very popular cousin, #57 stone.
4. Landscaping Borders or Fill
While it’s not typically used as a decorative top layer, #4 rock is great for filling in large gaps or building up height in landscaping projects. It also works well around foundations or as a buffer between structures and softer materials.