Guide
Tree roots lifting a sidewalk: the repair options and what to ask
A tree root lifts a sidewalk panel by growing thicker under it, so a repair that only treats the concrete tends to be temporary. Every repair is two decisions: what to do with the concrete, and what to do with the root. Cutting roots can weaken or kill the tree, so that part is an arborist's call. For a sidewalk along a street, ask the city as well.
The short answer
A tree lifts a sidewalk by growing. Iowa State University Extension explains that roots spread near the soil surface, grow beneath a sidewalk they meet, and get thicker as they mature. That outward growth presses on the sidewalk and can push sections up, buckling and lifting them, and widen small cracks. A repair that treats only the concrete leaves the root growing, which is why the step tends to come back.
So each repair is two decisions: what to do with the concrete, and what to do with the root. The concrete side runs from grinding to replacement, ramping or moving the walk. The root side belongs to an arborist, because the large roots near a sidewalk can be the ones holding the tree up. For a sidewalk along a street, ask the city as well.
Why roots lift sidewalk panels
- Roots thicken. Iowa State calls this secondary growth. As roots expand, they can push up sections of sidewalk, widen cracks, and displace whole sections.
- Compacted soil drives roots up. FHWA's 2013 pedestrian maintenance guide says street trees are often planted in soil compacted for vehicles, and roots in compacted soil migrate toward the surface for air and water, causing sidewalks to crack and heave.
- Small planting spaces. FHWA says tree pits are often the cause of sidewalk damage, because trees can outgrow the pit and buckle the sidewalk.
- Surface-rooted trees. FHWA says trees with larger surface roots may cause maintenance issues with nearby sidewalks, and recommends an arborist or other qualified professional for species selection.
Not every raised panel near a tree is a root problem. FHWA lists tree roots as one cause of sidewalk failure among several, with poor base soils, heavy vehicles and thin concrete. It cites a Cincinnati study that found a greater correlation between sidewalk failure and soil type than with nearby trees. It says a slab can also rise from expansive native soil, while noting that raised pavements are commonly caused by tree roots. Confirm a root is actually under the raised panel before choosing a repair. The sidewalk cracks guide covers patterns that point to soil.
The repair options
Two quick repairs leave the root alone:
- Asphalt wedge or patch. The U.S. Forest Service's 1998 bulletin on protecting tree roots during sidewalk work calls the wedge one of the simplest repairs, and usually temporary: it rarely corrects the problem but reduces the danger to pedestrians.
- Grinding. FHWA says root pop-ups and minor heaves are often ground down. Iowa State calls grinding and patching a temporary fix that won't stop further root growth. The bulletin says grinding is generally limited to less than 1 inch of displacement, and that if 50 percent of the slab's thickness is removed, the concrete's structural integrity may be lost. See sidewalk grinding, and grinding vs. saw cutting for the two ways of taking an edge down.
Mudjacking is not a root repair. FHWA says it is effective only on sunken sidewalks, and a root-lifted panel has risen.
When the panel comes out, the root becomes part of the job:
- Replace the panel. FHWA says many sidewalk failures are caused by poor subgrade or tree roots, and that a replaced sidewalk has a shortened life if those causes are left alone. In its description of replacement, it says tree roots are "very carefully cut if at all necessary." See sidewalk replacement.
- Ramp or bridge over the root. The Forest Service bulletin says a concrete ramp poured over uncut roots is stiff and can be expected to lift as roots expand. An asphalt ramp is flexible, so displacement would likely occur only over the root itself. Iowa State describes a replacement walk that slopes up and over the roots, supported by a thicker base or by concrete piers placed around the root system. For a public sidewalk, ask the city what slope it accepts.
- Switch to pavers. FHWA says some communities have been attracted to recycled rubber and plastic pavers around trees where roots have heaved concrete. If roots make them pitch, it says, the base can be regraded or the roots trimmed and the pavers reset. The Forest Service bulletin warns that individual pavers can be displaced as roots expand.
- Reroute or narrow the walk. Iowa State suggests moving the sidewalk away from the tree where possible: 4 to 6 feet from smaller trees and 10 feet or more from larger ones. Sometimes the walk can simply be narrowed.
Some measures go in with a new walk to slow a repeat. Iowa State says root barriers must be at least 18 inches deep, with the top above the soil and mulch, and that roots may still find a way under. FHWA says a gravel sub-base below sidewalks near street trees has been shown to reduce pavement damage on well-drained sites. It also describes root paths, trenches dug under an existing sidewalk so roots can reach new soil, as a low-cost retrofit. FHWA's own conclusion says an entire mini-guide could be written on how street trees affect sidewalks, so treat this list as a starting point.
What arborists and foresters say about cutting roots
This is where the sources are most cautious:
- The Forest Service bulletin says sidewalk repair and replacement usually involve cutting roots, and that research suggests injury to a tree's buttress roots could predispose it to decline or windthrow. It records that in 1990 a triple fatality in Toledo, Ohio, was associated with a falling tree whose roots were cut during sidewalk reconstruction.
- Iowa State says removing major or buttress roots can lead to branch and crown dieback or death, and can leave the tree structurally compromised and more likely to fail in high wind. It advises trying to avoid cutting roots over 2 inches in diameter. Where cutting is unavoidable, it says buttress roots should not be cut closer to the trunk than three times the trunk's diameter, measured three feet up. At 1.5 times or closer, it calls removing the tree a more prudent option. Depending on the tree's condition, size and value, it says removal may be better than damaging it during replacement, only for it to fail or die 3 to 5 years later.
- The International Society of Arboriculture (ISA) says grading, trenching and paving within a tree's critical root zone, the part essential for its health and stability, damage roots. Among an arborist's options it lists paving designed to bridge over roots. It says an arborist can prune roots out of the way before excavation, or cut them cleanly before any damage is done, and that construction damage may take many years to affect a tree.
Those figures frame the question; they are not a guide to cutting. Whether a given root can go is decided by an arborist looking at that tree.
Who to ask
About the tree, an arborist. ISA says Certified Arborists have passed a comprehensive exam and must keep up their education, and that the certification is nongovernmental and voluntary. Its TreesAreGood.org site has tools to find an arborist and verify a credential. Ask whether the root under the raised panel is structural, how far it is from the trunk, whether the walk can bridge or move instead, and how the tree should be protected during the work.
About a sidewalk along a street, the city. In Dallas, the City's Landscape and Tree Manual summary for single-family and duplex homeowners (2019; retrieved November 7, 2026) says: "Trees in the parkway are on city property and may not be removed without approval by the city arborist." A City of Dallas presentation on tree removal (August 2023; retrieved November 7, 2026) says: "Tree Removal in the ROW requires permission of the City of Dallas before it can be removed" (ROW is the right-of-way). Neither document says whether cutting a parkway tree's roots needs approval, so ask the city arborist before anyone cuts. For who must repair a Dallas sidewalk, see the Dallas guide. Elsewhere, start with public vs. private sidewalk repairs, and check with the city that the address is in.
About the concrete, the contractor. Ask which option they propose and why, what happens when they reach the root, who decides whether it is cut, and what they expect if it keeps growing.
Next steps
Record each lifted panel, the tree beside it and the height of the step with the walkway inspection checklist. The method comparison sorts the concrete side, the inquiry preparation guide gathers what a contractor needs, and you can ask about your project when ready.
| Option | What it does to the walk | What it does about the root | What the sources say |
|---|---|---|---|
| Asphalt wedge or patch | Fills the step between the low slab and the high one | Nothing | The Forest Service bulletin calls it usually temporary: it rarely corrects the problem but reduces the danger to pedestrians |
| Grinding | Wears the raised edge down | Nothing; the root keeps growing | Iowa State calls it a temporary fix. The bulletin says grinding is generally limited to less than 1 inch of displacement, and that removing 50 percent of the slab's thickness may cost the concrete its structural integrity |
| Panel replacement | Removes the panel and pours a new one | Exposes it; it may be cut, bridged or left | FHWA says roots are very carefully cut, if at all necessary, and that a replacement that ignores tree roots has a shortened life |
| Ramp or bridge over the root | New walk rises over the root instead of through it | Leaves it uncut | The bulletin says a concrete ramp is stiff and can be expected to lift as roots expand; an asphalt ramp is flexible, so movement tends to stay over the root itself |
| Pavers, including rubber and plastic pavers | Replaces the slab with units that can be lifted and reset | Leaves room to adjust the base | FHWA says recycled rubber and plastic pavers can be reset if roots make them pitch. The bulletin warns that individual pavers can be displaced as roots expand |
| Reroute or narrow the walk | Moves the walk away from the trunk | Gives the root more room | Iowa State suggests 4 to 6 feet from smaller trees and 10 feet or more from larger ones |
Questions on this page
Can a sidewalk lifted by a tree root just be ground down?
Often, as a stopgap. FHWA's maintenance guide says root pop-ups and minor heaves are often ground down. Iowa State University Extension calls grinding a temporary fix, because the root keeps lifting the sidewalk as it grows thicker. The U.S. Forest Service's 1998 bulletin says grinding is generally limited to less than 1 inch of displacement, and that removing 50 percent of the slab's thickness may cost the concrete its structural integrity. Expect the step to come back, and ask how the root will be handled next time.
Is it safe to cut tree roots to fix a sidewalk?
It depends on the root and the tree, and that is an arborist's call. Iowa State says removing major or buttress roots can lead to crown dieback or death, and can leave the tree more likely to fail in high wind. The Forest Service bulletin says injury to buttress roots could predispose a tree to decline or windthrow, and it records a 1990 triple fatality in Toledo, Ohio, associated with a falling tree whose roots were cut during sidewalk reconstruction. Have an arborist look at the tree before anyone cuts.
Who should I ask about a tree root lifting a sidewalk in Dallas?
Ask two people. An arborist can tell you what the tree can lose. For a sidewalk along the street, ask the City. A City of Dallas homeowner summary (2019; retrieved November 7, 2026) says: "Trees in the parkway are on city property and may not be removed without approval by the city arborist." The sources opened for this page do not say whether cutting a parkway tree's roots needs approval, so check with the city arborist before anyone cuts. Who must repair the sidewalk itself is covered in the Dallas sidewalk repair responsibility guide.