Tree Roots vs. Your Concrete: How to Save Both

Charlotte is a city of trees. Our towering willow oaks, majestic maples, and stately pines give our neighborhoods character and shade. But beneath the surface, those beautiful trees are waging a slow-motion war against your concrete.

Tree roots don't care about your driveway. They're programmed to grow toward water and nutrients, and they'll lift, crack, and destroy anything in their path. In neighborhoods like Dilworth, Myers Park, and Plaza Midwood—where trees are 50-100 years old—root damage is epidemic.

The good news? You don't have to choose between your trees and your concrete. At Charlotte Concrete Repair, we specialize in solutions that repair the damage and prevent it from recurring, all without harming your trees.

How Tree Roots Destroy Concrete

Trees are incredibly strong. A single root can exert thousands of pounds of upward pressure as it grows. Concrete, despite being hard, is relatively brittle. It can't flex; it can only crack.

Here's what happens:

1. Root Expansion: Roots grow radially from the trunk, seeking moisture. They typically stay in the top 12-18 inches of soil—exactly where your concrete sits.
2. Upward Pressure: As a root thickens (growing by fractions of an inch per year), it pushes against the bottom of the slab.
3. Lifting: The slab tilts, creating a "tented" effect. One edge rises while the other stays down.
4. Cracking: The bending stress eventually exceeds the concrete's strength. It snaps, often in a jagged line parallel to the root.
5. Continued Damage: Unless the root is addressed, it keeps growing and the damage worsens each year.

Repair Options: From Conservative to Comprehensive

Option 1: Grinding (Minor Lift)

When it works: The lift is less than 1 inch, and the root is small or stable.

We grind down the raised edge to eliminate the trip hazard. This is fast, cheap, and non-invasive. However, it doesn't address the root, so the problem may recur in several years. For small roots that are nearing the end of their growth, this can be a permanent solution. For aggressive roots, it's a temporary fix.

Option 2: Sectional Replacement with Root Pruning

When it works: The lift is significant, and the root is accessible.

This is our most common solution. We cut out the damaged panel, excavate to expose the root, and carefully prune it back. We then compact a new base and pour a new panel.

Is root pruning safe for the tree? Generally, yes—if done correctly. Trees can tolerate losing some roots, especially if we cut cleanly (not tear) and limit pruning to one side of the tree at a time. We never remove more than 20-25% of a tree's root zone in a single project.

Option 3: Root Barrier Installation

When it works: After repair, to prevent future damage.

A root barrier is a physical wall installed in the soil that redirects roots away from the concrete. We typically use high-density polyethylene panels, 18-24 inches deep, installed vertically along the edge of the new slab. Roots hit the barrier and are forced to grow downward or laterally, away from your hardscape.

This is a long-term investment that can prevent repeat damage for decades.

Option 4: Bridging (For Critical Roots)

When it works: The root is a major structural root that cannot be cut.

Some roots are too important to prune—they provide critical stability for the tree. In these cases, we build a "bridge" over the root. We create a reinforced concrete section with a void underneath that allows the root to continue growing without lifting the slab. This is more complex and expensive, but it saves both the tree and the concrete.

Working with Arborists

For valuable or heritage trees, we recommend consulting a certified arborist before any root pruning. They can assess the tree's health, identify which roots are critical, and advise on how much pruning is safe.

We're happy to coordinate with your arborist—or recommend one we trust—to ensure the tree stays healthy while your concrete is repaired.

Prevention: Planning for the Future

If you're installing new concrete near trees, plan ahead:

• Increase distance: The further from the trunk, the smaller the roots. If possible, route sidewalks and driveways away from large trees.
• Install barriers proactively: A root barrier installed during initial construction is far cheaper than repairs later.
• Choose the right trees: Some species have less aggressive root systems. Consult a nursery or arborist when planting near hardscape.
• Thicken the slab: A 6-inch slab is more resistant to lifting than a 4-inch slab. It costs more but resists root pressure longer.

Conclusion

Tree root damage is the most common concrete problem in Charlotte's mature neighborhoods. But it's solvable—without cutting down the trees that give our city its character.

At Charlotte Concrete Repair, we've repaired hundreds of root-damaged sidewalks, driveways, and patios. We know how to work with roots, not just against them. If you're battling a tree that's winning, call us. We'll assess the situation, discuss your options, and find a solution that protects both your concrete and your canopy.