Why Tree Roots Lift Concrete Walkways and What Homeowners Can Do About It

A raised section of concrete near a tree is a common sight in older neighborhoods. One slab sits higher than the next. A crack runs across the walkway. Sometimes, you can even see a thick root pushing against the concrete.

Tree roots lift concrete walkways as they grow thicker beneath the surface. The problem is more likely when trees have limited room to spread or when compacted soil forces roots to grow close to the surface.

The good news is that you don't always have to remove the tree to fix the walkway. The right approach depends on the condition of the concrete and how close the roots are to the trunk.

Why Do Tree Roots Push Up Concrete?

Tree roots grow outward in search of water, oxygen, and nutrients. Most of the roots that absorb these nutrients are found in the upper layers of soil.

As a tree matures, its larger roots become thicker. When a root grows beneath a concrete walkway, it can gradually push the slab upward. Because concrete cannot bend to accommodate the growing root, the walkway may eventually lift, tilt, or crack.

The damage often develops over several years. A walkway that was perfectly level when the tree was young can turn uneven as the tree grows older.

Roots aren’t behind every crack near a tree. Concrete can also shrink or break due to poor installation, settling soil, or repeated heavy loads. A nearby tree doesn't automatically mean root damage is responsible.

What Makes Some Walkways More Vulnerable?

Two trees of the same species can grow beside concrete walkways with very different results. The surrounding soil and available growing space make a big difference.

Limited Space Around the Tree

A tree planted in a narrow strip between the street and sidewalk has little room to develop its roots.

As the tree grows, its roots may extend beneath the surrounding pavement. Larger roots can eventually push the concrete and lift it.

This is especially common in urban neighborhoods where mature trees share small planting areas with sidewalks and driveways.

Compacted Soil

Roots need oxygen as well as water. When soil is heavily compacted, roots struggle to push deeper into the ground.

Instead, they may spread through the top layers of soil or into the gravel beneath a walkway, where growing conditions are more favorable.

This is one reason paving and soil conditions should be considered together when designing outdoor spaces.

Concrete Installed Too Close to the Trunk

A young tree may have plenty of room for natural root growth when a walkway is first installed. That space can become inadequate as the trunk and major roots grow.

Concrete placed close to the tree leaves little room for this natural growth. Over time, the roots and paving may come into conflict.

How to Tell If Tree Roots Are Damaging Your Walkway

Root-related damage often has a recognizable pattern. One concrete slab may lift while the surrounding sections remain level. In other cases, a crack develops near the tree and gradually widens.

Look for these signs:

• A raised concrete edge close to a tree.
• A slab tilting upward toward the trunk
• Roots visible beneath or next to the walkway
• Cracks running the same way as a large surface root
• A gap opening between neighboring slabs

These signs can help you identify a possible cause, but they aren't proof on their own.

For example, a sinking slab can create the same uneven surface as a rising one. Before deciding on a repair, it worth determine whether the concrete has been lifted by a root or has settled due to underlying problems.

Can You Fix a Root-Damaged Walkway Without Removing the Tree?

In many cases, yes.

The goal is to restore a safe walking surface while leaving the tree's important roots intact. There are several ways to do this, but not every method works for every walkway.

Grind Down a Slightly Raised Concrete Edge

When two slabs have a very little to low difference in height, concrete grinding may help create a smoother transition.

A contractor removes a controlled amount of concrete from the raised edge. This reduces the trip hazard without excavating around the roots.

However, grinding has limits. It does not stop a root growth or fix a slab that has moved too far. It may also be unsuitable if too much concrete would need to be removed.

Replace the Damaged Concrete Slab

If the concrete is badly cracked or has shifted significantly, replacing the affected section may be the better option.

Simply pouring new concrete over the same roots can lead to another uneven walkway. The repair should account for the roots beneath the concrete and allow room for future growth wherever possible.

This is particularly important for public sidewalks. Repairing cracked and uneven concrete sidewalks in NYC requires compliance with local construction requirements as well as tree-root protection. The city also restricts work involving the roots of City-owned trees, and certain work may require a permit from the NYC Parks Department.

Getting a tree assessment before construction can help homeowners avoid unnecessary damage to a mature street tree.

Adjust the Walkway Around the Roots

Sometimes, modifying the walkway makes more sense than disturbing the tree.

A garden path may be moved slightly farther from the trunk. Where space is available, a curved route can provide a comfortable walking surface while avoiding major roots.

For an existing concrete walkway, a carefully designed raised section may allow pedestrians to pass over the roots without cutting them.

These changes can take more planning, but they may offer a longer-lasting solution when the tree is healthy and worth preserving.

Consider Flexible or Modular Paving

Interlocking pavers can be useful for some garden paths near trees. Unlike a single concrete slab, individual pavers are easy to lift and adjust if the surface moves. This can make future maintenance easier.

The base still needs proper preparation. Installing pavers directly over exposed roots or digging deeply around the tree can cause problems of its own.

Porous paving may also be worth considering in suitable locations. It allows some rainwater to pass through the surface, though it doesn't eliminate the possibility of roots lifting the walkway.

Why Cutting Tree Roots Can Make the Problem Worse

It might seem easiest to cut the root and put the concrete back where it belongs. Unfortunately, that decision can cause more serious problems than the uneven walkway.

Large roots help anchor a tree in the ground. Removing one close to the trunk can weaken its stability, especially during strong winds.

Root cutting can also reduce the tree's ability to absorb water and nutrients. The effects may not become obvious immediately.

A tree might continue to look healthy after losing an important root, even though its stability has been compromised.

That's why major root cutting should never be treated as a routine part of sidewalk repair.

A qualified arborist can assess the roots and advise whether the proposed work is likely to harm the tree. For street trees, local regulations may also limit what can be cut or disturbed.

How to Prevent Tree Roots From Lifting Walkways

Prevention starts with giving trees enough space to grow. If you're planning a new garden path or replacing an old walkway, consider the tree's mature size rather than its current appearance.

Leave room for root growth. Avoid placing concrete too close to the trunk when the layout allows another option.

Choose trees that suit the planting area. Large trees need generous rooting space. A species that works well in an open yard may struggle in a narrow planting strip.

Protect the surrounding soil. Repeated vehicle traffic and heavy equipment can compact the ground around roots. Keeping these activities away from the tree helps preserve healthier growing conditions.

Plan the walkway and planting area together. A path that curves around a tree may work better over time than one built directly across its major roots.

If you're designing a new paved area, ask a landscape professional about soil preparation and whether structural soil or other root-friendly construction methods would suit the site.

These measures can't guarantee that roots will never affect a walkway. They can, however, reduce the likelihood of a conflict as the tree grows.

When Should You Call a Professional?

A small crack doesn't always require a major repair. But once a concrete slab starts creating a noticeable trip hazard, the problem deserves attention.

You should also seek professional advice if:

• Several slabs have shifted near the same tree.
• A large root is exposed beneath broken concrete.
• The walkway continues to rise after previous repairs.
• Repair work would require digging close to the trunk.
• The tree shows signs of leaning, root damage, or declining health.

For private garden paths, a landscape contractor may be able to recommend a suitable paving option. If major roots are involved, an arborist should assess the tree before excavation begins.

Public sidewalks may have additional requirements. In New York City, for example, the Parks Department operates a Trees and Sidewalks Repair Program for qualifying damage caused by City-owned trees beside one-, two-, and three-family homes. Homeowners can request an inspection through NYC 311.

A Healthy Tree and a Safe Walkway Can Coexist

A raised walkway doesn't automatically mean a tree needs to come down.

Often, the better solution is to work with the tree's existing root system rather than against it. That may mean smoothing a minor uneven edge, replacing a damaged slab with proper root protection, or changing the path to give the tree more space.

The important part is identifying what's happening beneath the concrete before starting repairs.

A thoughtful approach can keep the walkway safe without sacrificing the shade and beauty of a mature tree.