The #1 Cause of Patio Failure — and How to Fix It in the Lowcountry

Most contractors talk about pavers, borders, patterns, and colors.
But NONE of that matters unless the drainage is right.

Charleston homeowners deal with:
• heavy summer storms
• sandy and shifting soil
• standing water
• humidity
• downspout flooding
• poor grading from builders

If drainage is wrong, your backyard will fail — no matter how good the materials are.

This guide explains how Charleston drainage works and what to avoid.

1. What Happens When Drainage Is Wrong?

• Pavers shift and sink
• Polymeric sand washes out
• Mosquito breeding zones form
• Water sits against your foundation
• Mold and algae grow rapidly
• Grass dies
• Plants rot
• Rock beds wash out
• Flooding becomes worse over time

In Charleston, poor drainage can ruin a $20,000–$60,000 patio.

2. The 4 Drainage Systems Every Charleston Yard Needs

A. Slope & grading

Every patio must pitch at 1–2% away from the home.

B. Open-graded base (NOT dirt or sand)

Charleston patios should be built on:
• 57 stone
• Geo-fabric
• Stone dust / 789 bedding layer

NEVER on sand.

C. French drains

Prevent water from pooling near patios or foundations.

D. Downspout rerouting

90% of water issues come from downspouts with nowhere to go.

3. Why Polymeric Sand Fails in Charleston

Humidity + storms = poly sand disaster.

It:
• hazes
• traps water
• grows mold
• weakens over time
• becomes sticky
• stains pavers
• NEVER fully hardens in Charleston humidity

Use 789 sand or stone dust instead.

4. How to Tell If Your Yard Has Drainage Problems

Look for:
• puddles after 2 hours
• settling or sinking
• mildew on concrete
• insects around wet areas
• dead grass patches
• puddles near foundation
• mulch washing away
• standing water odor
• downspout erosion lines

If you see ANY of these — you need drainage improvements.

5. Real Drainage Solutions for Charleston Yards

Fix #1: Regrading the entire yard

Often required for older homes.

Fix #2: Installing French drains

Ideal for soggy yards or low spots.

Fix #3: Rerouting downspouts underground

This one solves problems instantly.

Fix #4: Adding an open-graded patio base

Prevents sinking and washouts.

Fix #5: Channel drains in heavy water flow areas

6. How Much Does Drainage Cost in Charleston? (Real Pricing)

• Basic downspout reroute: $300–$600
• French drain section: $900–$2,500
• Full-yard French system: $3,500–$7,500
• Regrading: $800–$4,000
• Channel drains: $900–$2,200

7. How Drainage Makes Your Patio Last 20–50 Years

The base + drainage is what gives a patio:
• structural integrity
• stability
• longevity
• resistance to storms
• resistance to shifting soil

Drainage = the foundation of everything.

Need a drainage-first design for your Charleston backyard?

We design outdoor living spaces that LAST — built specifically for the Lowcountry.

Text or call 845-300-5088 to book a drainage-focused consultation.