Gravel might seem straightforward, right? Just a bunch of small rocks. But try to decide may seem more difficult than it seems. At Newington Stong & Garden, we’ll give you the best advice you can get at no additional cost. Our years of experience have helped hundreds in getting the right size gravel for their needs. Choosing the right size gravel goes beyond just looks; it’s essential for the functionality, durability, and safety of your project. Whether you’re laying down a driveway, crafting a pathway, enhancing drainage, or adding some decorative flair, the size of your gravel really does matter.
Let’s dive into how to pick the perfect gravel size for your needs.
Understanding Gravel Sizes: What Do the Numbers Mean?
Gravel is usually sorted by size using screens, and the size designation often refers to the diameter of the stones. You might come across numbers (#57, #8, #10), descriptive names (like pea gravel, river rock, or drainage stone), or measurements in inches. Here’s a handy guide to some common sizes (keep in mind that exact sizes can vary a bit depending on where you are and your supplier):
- Fines/Stone Dust (#10 or Screenings): These are very tiny particles, almost like sand, often less than ¼ inch. They’re great for creating a smooth, compactable base or filling in the gaps between pavers.
- Small Gravel (#8, #89, #9): Usually around ¼ inch to ½ inch. This category often includes “pea gravel” (if it’s rounded) or small crushed chips.
- Medium Gravel (#57, #67): A popular size, typically ranging from ½ inch to 1 inch (often described as being about the size of a dime to a quarter). #57 is widely used for a variety of applications.
- Large Gravel (#3, #4, #411): These stones range from 1 inch to 2.5 inches or even larger. They’re used for substantial bases, drainage, or decorative features.
- Oversized/Riprap: These are very large stones (4 inches and up). They’re typically used for erosion control, shoreline stabilization, or significant drainage ditches.
Key Distinction: Crushed Stone vs. River Rock/Pea Gravel
- Crushed Stone: This type features sharp, angular edges that come from mechanically crushing larger rocks. These jagged edges fit together nicely, creating a solid, compact surface that’s perfect for bases and driveways.
- River Rock/Pea Gravel: These stones are naturally rounded and smooth, thanks to water erosion. They tend to shift around more easily and don’t compact as well, but they feel great underfoot and look lovely in any landscape.
Matching Gravel Size to Your Application (Choosing the right size is crucial)
1. Driveways:
- Top Layer: For the top layer, medium crushed stone like #57 is a favorite. Its angular pieces lock together effectively under the weight of vehicles, ensuring stability and minimizing scattering. It’s best to steer clear of pea gravel or small river rock, as they can shift easily, get caught in tire treads, and make it tough to gain traction.
- Base Layer: A larger crushed stone, such as #3 or #4, is typically used for the base layer, providing a strong foundation. Sometimes, “crusher run” (a blend of crushed stone and fines) is chosen for its excellent compaction abilities.
2. Walkways and Paths:
- Comfort & Stability: For walkways, smaller gravel is usually the way to go for comfort. #8 or #9 crushed stone strikes a nice balance between stability and ease of walking.
- Pea Gravel: This can work for low-traffic paths because of its attractive appearance and comfortable feel, but keep in mind it can shift and might need edging to keep it in place. It’s not the best choice for sloped paths.
- Stone Dust/Fines: This can serve as a top layer for a very firm, smooth path, similar to decomposed granite, but be cautious as drainage can be slower.
3. Patios and Seating Areas:
- Stability for Furniture: Just like with walkways, stability is key for patio furniture. #8 crushed stone is often a solid option since it compacts reasonably well.
- Pea Gravel: While it looks great, furniture legs can sink into pea gravel, making it less stable. If you decide to use it, make sure there’s a well-compacted base underneath.
4. Drainage:
- When it comes to drainage, especially with French drains and behind retaining walls, water flow is crucial. You want to use gravel that has plenty of void space to let water pass through without a hitch. Opt for larger, clean stones—like #57 or bigger crushed stone or river rock in the 1-2 inch range. Just steer clear of gravel with fines, as those little particles can clog up the drain over time.
5. Base Layers (Under Pavers, Concrete Slabs):
- Now, let’s talk about base layers for pavers and concrete slabs. A solid, compactable base is essential. Crusher run, like #411, or #57 stone (sometimes mixed with fines depending on local practices) are popular choices. The combination of different sizes and angular shapes allows for great compaction, which creates a stable foundation that drains well. You might also want to add a layer of smaller stone or sand right under the pavers for leveling.
6. Decorative Landscaping (Mulch Substitute, Borders):
- When it comes to decorative landscaping, aesthetics are key. The size of the material you choose really depends on the look you’re going for. For ground cover, pea gravel or #8 and #9 stones (whether crushed or rounded) make excellent inorganic mulch in garden beds. If you’re looking to add some accents or borders, larger river rocks (1-3 inches or more) or even small riprap can add visual interest around features or along borders. For dry creek beds, mixing sizes from #57 up to larger river rocks and small boulders can create a beautiful, natural appearance.
7. Play Areas:
- And let’s not forget about play areas. Safety should always come first. While pea gravel used to be a go-to option, it’s often not recommended these days due to compaction issues and potential choking hazards for little ones. Be sure to check your local playground safety guidelines. Rounded pea gravel might be okay in some situations, but engineered wood fiber or rubber mulch are generally seen as safer alternatives. If you do decide to use gravel, make sure it’s small, rounded, and free of any sharp edges.
Other Factors to Consider
Other factors to keep in mind include slope and maintenance. Smaller, rounded gravel like pea gravel can easily wash away or shift downhill on slopes, so it’s better to use angular, crushed stone for more stability on inclines. Plus, smaller gravel tends to get kicked around more easily and can trap leaves and debris more than larger stones.