Japanese Maple Roots Lifting Patio: What to Do?

A 20-year-old Japanese maple has pushed up a concrete patio by two inches. The homeowner plans to replace the patio with tile and wonders if the tree's roots will continue to cause damage or if growth slows with age.

Tree Roots Keep Growing

Trees are living organisms; as they add canopy, their root systems expand to supply water and nutrients. While the most rapid expansion occurs in youth, roots never completely stop growing. In this case, it took two decades to lift the slab 2 inches—suggesting a relatively slow pace.

Mitigation Strategies

• Add soil cover: Applying 3–4 inches of soil over surface roots before repaving can buy another 15–20 years before further lifting.
• Root barriers: Trenching along the patio edge and installing a vertical root barrier (high-density polyethylene, 30–36 inches deep) deflects roots downward.
• Selective root pruning: Up to 25% of a tree's roots can be cut without severe harm, but this should be done by a certified arborist to avoid destabilizing the tree.

Professional Assessment Recommended

Because site conditions vary, consult a local ISA Certified Arborist. They can evaluate root distribution, soil type, and proximity to structures, then design a long-term management plan. Find one at isa-arbor.com.