Thinking about installing a concrete patio but not sure what base to use? You’re not alone. A solid foundation is the difference between a patio that lasts for decades and one that cracks, sinks, or becomes uneven after a few rainy seasons.

In this guide, we’ll answer the exact question: What’s the best base for a concrete patio? — and explain it in simple terms. Whether you're planning a DIY project or hiring professionals like Xcelent Concrete Services in Portland, this article is written for you.

Let’s dig in.

Why the Base of Your Concrete Patio Actually Matters

It might seem like concrete is tough enough on its own — and it is! But without the right base, your patio is like a house without a proper foundation.

Here’s what a bad base can lead to:

• Cracking and crumbling
  
  

• Pooling water or poor drainage
  
  

• Weed growth or shifting slabs
  
  

• Costly repairs (and stress)
  
  

So, what’s the solution? A strong, well-prepared base.

Quick Answer: What’s the Best Base for a Concrete Patio?

The best base for a concrete patio is compacted gravel or crushed stone topped with a layer of sand.

Why? Because:

• Gravel provides drainage (goodbye water damage)
  
  

• Compacted stone prevents shifting and settling
  
  

• Sand helps level and smooth the surface
  
  

You’ll often hear pros refer to this as a “granular base.”

Now let’s explore the options so you can make the smartest choice.

Option 1: Compacted Gravel or Crushed Stone (Highly Recommended)

This is the gold standard — used by nearly every professional concrete contractor in Portland.

How it works:

• A layer of 4–6 inches of compacted gravel is laid down.
  
  

• It's leveled and pressed tight using a plate compactor.
  
  

• Then a 1-inch layer of sand is often spread for extra smoothness before pouring concrete.
  
  

Pros:
✅ Excellent drainage
✅ Long-term stability
✅ Reduces the risk of cracks
✅ Works well in wet climates (hello, Portland!)

Cons:
❌ Requires equipment to compact properly
❌ A bit more work upfront — but totally worth it

Expert Tip: At Xcelent Concrete Services, we always use compacted gravel as the foundation for patios in Portland because of our rainy weather. It’s what keeps our patios strong and our customers happy for years.

Option 2: Sand Alone (Not Recommended)

Some DIYers try to use just sand underneath concrete. It’s easier to level and spread, sure — but it’s not stable enough for a concrete slab.

Why it’s risky:

• Sand shifts over time, especially with rain
  
  

• Can cause uneven surfaces and cracks
  
  

• Doesn’t drain water as well as gravel
  
  

You don’t want your patio to sink after a few months — trust us.

Option 3: Concrete Over Grass or Dirt (Please Don’t!)

You might be tempted to just pour concrete directly on dirt or grass. It's faster and cheaper upfront… but this shortcut will cost you later.

Why it fails:

• Dirt compresses unevenly
  
  

• Grass decomposes, causing voids under the slab
  
  

• No drainage means water pools under the slab
  
  

• Leads to major cracking, lifting, or sinking
  
  

Bottom line: Never pour concrete directly over soil. It’s a shortcut that backfires.

What’s the Right Thickness for Your Concrete Patio?

Since we’re building a strong base, let’s talk about the concrete itself.

For patios, the ideal thickness is:

• 4 inches for standard patios (foot traffic only)
  
  

• 5–6 inches if you plan to park heavy objects (like hot tubs)
  
  

Reinforcing with rebar or wire mesh also adds long-term strength — especially for large patios.

What About Portland’s Rainy Weather?

We get it — Portland isn’t known for dry, sunny days. That’s exactly why your concrete base matters even more.

Here’s how we deal with it:

• Use well-draining gravel as the base
  
  

• Slightly slope the patio to encourage runoff
  
  

• Add expansion joints to control cracking
  
  

At Xcelent Concrete Services, we install patios that can handle rain without breaking a sweat. We’ve been doing it in Portland for over 18 years.

Step-by-Step: How a Pro Installs the Right Base

Here’s a simplified version of how professionals build a patio base:

1. Excavate the area — remove grass and topsoil.
   
   

2. Level the ground and slope it slightly for drainage.
   
   

3. Add 4–6 inches of gravel or crushed stone.
   
   

4. Compact it using a mechanical plate compactor.
   
   

5. Add a layer of sand (optional for smoother finish).
   
   

6. Pour the concrete and finish with expansion joints and sealing.
   
   

Need someone to handle all of that? We’ve got you.

Common Questions (Real Talk)

Q: Can I skip the gravel base to save money?
A: You can — but you’ll likely pay more for repairs later. A proper base is a smart investment.

Q: How long does the gravel base need to settle?
A: If compacted well, it’s ready the same day. No need to wait weeks.

Q: Do I need a vapor barrier?
A: Not always for patios, but in some wet areas, it helps prevent moisture issues. We assess that case by case.

Here’s What to Do Next

If you’re in Portland and want a concrete patio that lasts — not one that cracks after a year — don’t cut corners on the base.

Xcelent Concrete Services specializes in:

• Concrete patio installation
  
  

• Proper base preparation
  
  

• Driveways, walkways, stairs, and more
  
  

Want to talk with a local expert?
📞 Call us today or visit xcelentconcrete.com

Final Thoughts: Don’t Just Pour It — Build It Right

So, what’s the best base for a concrete patio?

Compacted gravel + sand = long-lasting, weather-ready patios.

Whether you're DIY-ing or hiring pros, this is the foundation your outdoor space deserves. And if you want it done right the first time, we’re here to help.

👉 Got questions? Feel free to reach out — we love talking concrete.