What Kind of Aggregate Base Is Best for Drainage?

Choosing the wrong base material for soil can lead to headaches. Whether you’re prepping for a new driveway, laying a patio, or working on landscaping around your home or business, the base you build on makes all the difference in the project’s quality and longevity. Get it wrong, and you could be dealing with water pooling, soft spots, or long-term structural damage.

The aggregate base isn’t the part you see; it’s what’s underneath the decorative layer. This foundation plays a key role in how water moves (or doesn’t move) through your project. It also supports everything above it, from pavers to parked vehicles.

Below, we’ll help you answer a question that can save you time and frustration later: What kind of aggregate base is best for drainage?

Start With Your Soil Type

Before you order any material, take a moment to understand the soil you’re working with. It might not be the most exciting part of the project, but your soil determines how well water drains and how effective your aggregate base will be.

Let’s cover the three soil types you’re most likely to encounter.

Clay-Heavy Soil

You’ll usually spot clay soil by its dense, sticky texture. If you can form a ball that holds together in your hand, you’re dealing with clay. This type of soil retains water longer than most and drains slowly, making it a challenging match for projects that require dry and stable conditions.

Without the right base material, water can sit on top of clay soils for days. That can lead to erosion, sinking, or heaving during colder months. In other words, if your base can’t help water move away, it’s going to get stuck and take your project with it.

Sandy or Loose Soils

Sandy soils feel grainy when rubbed between your fingers and don’t hold their shape when squeezed. Water drains through them quickly, which sounds like a good thing until you realize how easily this kind of soil shifts and settles.

The challenge with sandy soil isn’t drainage; it’s stability. Without a base material that compacts well, your finished surface might shift, rut, or sink over time. Think of sandy soils as needing a little extra structure to lock things into place.

Mixed or Loamy Soils

Loamy soil is what most people wish they had. It crumbles nicely in your hand and holds a bit of shape without being sticky or overly loose. It’s usually a blend of sand, silt, and clay, which gives it decent drainage and good stability.

That said, even loamy soil can become problematic if you place the wrong base on top. It can still shift when saturated or freeze unevenly in the winter. While loamy soil provides more flexibility, it’s still essential to pair it with a base that strikes a balance between compaction and permeability.

Best Base for Driveways

Driveways take a beating. Daily traffic, parked vehicles, and winter freeze-thaw cycles all put serious stress on the surface. Without a solid base underneath, problems like rutting, sinking, or water pooling aren’t far behind.

Two of the most reliable materials for driveway bases are 3/4-inch crushed gravel and road base. The right pick, though, depends on your soil conditions. Crushed stone drains better and resists movement in clay-heavy soils, while road base offers excellent compaction in loose or sandy areas. If you’re working with loamy or mixed soils, either option can work well.

For clay soils that hold water, you might also consider laying down a geotextile fabric before installing your base. Doing this separates the aggregate from the wet soil underneath.

Best Base for Walkways and Patios

Walkways and patios call for a base that drains well but also stays put. You want something compactable and fine enough to create a level surface without holding onto moisture or shifting with foot traffic.

In most cases, materials like decomposed granite, screenings, or 1/4-inch minus provide a good balance. These are fine, angular aggregates that compact tightly, giving you a firm surface that still allows water to seep through. If you’re unsure what’s available in your area, a quick call to aggregate haulers like Thomas Sand and Gravel can help you confirm what’s in stock or learn about a suitable alternative.

Soil type plays a part here, too. When you’re working with clay-heavy soils, drainage is going to be your biggest concern. In that case, a deeper base or the addition of a coarser sublayer, like crushed rock, can help. For sandy soils that shift more easily, using a material with a mix of fines, such as 1/4-inch minus, will provide more stability.

But before you pour the base material, it’s a good idea to install a weed barrier or geotextile fabric. This helps keep the aggregate from mixing into the soil over time and blocks unwanted growth, especially in areas with loose or loamy ground.

Best Base for Landscaping and Garden Beds

When it comes to landscape features, particularly those near structures or around garden beds, the wrong base material can do more harm than good. You want something that helps water flow away—not toward—your foundation or plant roots.

This is where washed rock, pea gravel, and river rock often come in. These rounded aggregates don’t compact the same way crushed materials do, but they allow water to pass through quickly. That makes them useful for creating dry creek beds, lining garden borders, or improving drainage near downspouts and hardscape edges.

If your soil already drains poorly, these materials can provide a clear drainage path to redirect water where it needs to go. In sandier soil, they reduce erosion and protect plant beds from being washed out during storms.

What To Consider Before Ordering

Before scheduling an aggregate delivery, have a clear idea of the actual quantity of material you’ll need. While it’s common to hear people ask about ordering “a ton,” aggregate is often measured in cubic yards. The total amount you need depends on the square footage, depth, and type of aggregate you’re using.

For a typical residential walkway or garden project, a 2-ton minimum might be more than enough. That’s one of the advantages Thomas Sand and Gravel offers, compared to some competitors that require 15-ton minimums. It’s a big difference in flexibility, particularly if you’re working in a small space or don’t have room to store extra material.

For business owners working on larger pads or parking areas, those quantities scale up quickly. In either case, ordering the right amount the first time helps avoid project delays, wasted costs, or messy cleanup.

Don’t Skip This Step

Are you still wondering what kind of aggregate base is best for drainage? The best way to get a clear answer is to talk it through with someone who understands how soil, slope, and surface conditions all come together. At Thomas Sand and Gravel, we’re happy to help you make that call.

Whether you’re building a driveway, a patio, or a drainage channel, we’ll walk you through your options, calculate the material you need, and recommend the right product for the job.

We offer fast, dependable aggregate hauling services across Northern Utah, with a 2-ton minimum, short delivery windows, and drop-offs precisely where you need them. From residential jobs to commercial projects, Thomas Sand and Gravel will help you keep things simple and on schedule.