Tree roots usually extend two to three times the width of the tree’s crown, meaning a tree with a 10-foot-wide canopy can have roots spreading 20 to 30 feet in all directions. In an apartment complex, these spreading roots can conflict with parking spaces, drive lanes, and walkways, since builders usually place these structures just a short distance from the trees.
The result can be a ridge in the tarmac, a fine crack that widens each season, or a bump that knocks a resident’s tire.
We repair parking lots damaged by tree roots for property managers, owners, and HOAs across the country, and we know that cutting roots or filling cracks usually doesn’t solve the problem. In this article, we explain how tree roots break asphalt, why tree roots affect apartment parking lots more than most other property types, and how we repair the damage permanently.
Overview
- Tree roots grow shallow, and the asphalt lies directly in their way.
- As the roots thicken, they lift the pavement and move into cracks and edges in search of air and moisture.
- In apartment complexes, narrow strips of asphalt and narrow planting areas increase the risk.
- Raised pavement poses a tripping hazard and constitutes an accessibility violation.
- A permanent repair involves pavement work, root management, and more room for planting.
Why Apartment Lots Put Trees and Asphalt in Conflict
Most tree roots stay near the surface.A report in Arborist News notes that most roots lie in the top foot of soil, exactly where builders place the aggregate base and asphalt. Because of their shallow position, the roots come into direct contact with the pavement structure.
The parking areas of apartments make the problem worse since it is common for designers to plant trees in the narrow strips located at the ends of rows of parking spaces, along the fronts of the buildings, and between the parking bays; these strips provide the tree roots with very little soil in which to grow. The roots then grow under the curb and into the adjacent loose soil beneath your asphalt. Moreover, many apartment parking lots have thinner pavement sections than highways or large retail lots. A research paper from Wageningen University found that root damage mostly occurs in pavements that are lightly constructed, which applies well to many residential parking areas.
How Roots Break, Lift, and Undermine Asphalt
Roots damage pavement in three ways, each requiring a separate repair.
As a root grows, it thickens each year and constantly pushes upward on the asphalt above. The asphalt gives way for a time before cracking along the root’s line and bulging into a ridge; this pattern is most common within a few feet of the trunk and along the curb line.
After oxygen and water, research carried out by Arborist News showed that roots usually do not go very far beneath solid pavement and may disappear within just a few inches. Roots favour soil that holds both air and water, so they grow most vigorously at pavement edges, inside cracks, around damaged areas, and along utility cut lines. These openings concentrate root damage at joints and borders rather than distributing it evenly across the entire area.
When the soil dries out, a big tree draws a lot of water from the ground. As clay soils lose moisture, they shrink, and the area underneath the asphalt sinks with them. This creates a shallow dip or depression near the tree—not a ridge—and that dip gathers water, which further weakens the pavement.
Reading the Warning Signs
The shape and position of the damage indicate the root problem we are dealing with; therefore, use the table as a rapid field guide during your next visit to a property.
| What you see | What the roots are doing | What we recommend |
| Ridge running parallel to the curb | Lateral roots lifting the asphalt edge | Remove the raised section, manage the root, and rebuild the base |
| Radial cracks fanning out from a planting island | Roots pushing up from several directions | Evaluate the tree, enlarge the island, and repave the damaged area |
| Bump in a drive aisle 10 to 20 feet from a tree | A single large root crossing under the pavement | Cut out the asphalt and let an arborist assess the root |
| Dip or depression that deepens in summer | Soil shrinking as roots pull out moisture | Rebuild the base and correct drainage |
| Cracks that follow a patch or utility cut | Roots entering the weak, aerated backfill | Replace the patch with properly compacted base |
| Lifted curb or catch basin frame | Roots displacing hard structures | Reset the structure and protect it with a barrier |
Which Trees and Distances Matter Most
Trees do not damage pavements equally. According to the Wageningen study, trees with shallow roots are more likely to damage pavement than those with deep roots, and smaller trees generally cause less damage than larger ones. Species that grow quickly and have shallow roots, for example, willow, poplar, silver maple, and sycamore, should therefore receive extra attention in any apartment yard.
It takes only a minute to work out the size of a tree’s root zone. The Georgia Urban Forest Council has a straightforward formula for the critical root zone: multiply the trunk diameter, measured in inches at 4.5 feet above the ground, by 1.3 feet. A tree with a trunk diameter of 12 inches therefore has a critical root zone radius of approximately 15.6 feet, and any asphalt lying within that radius poses a risk. Walk out that radius for every mature tree near a parking area, and note the pavement sections you find within it.
Trip Hazards and Accessibility Rules
Root damage causes not just a maintenance problem. It can injure a resident if a raised crack appears in a walkway or other accessible route, and it can cause your property to fail to meet accessibility standards. The 2010 ADA Standards permit a vertical change in level of only one quarter of an inch, call for a bevel when the change is between one quarter and one half of an inch, and require a ramp for any increase beyond that, as the ADA level change limits illustrated here show. A root ridge near an accessible stall or building entrance can exceed that limit within one season.
Managers should treat any lifted pavement on a walking route as a priority repair, since resident complaints, incident reports, and photographs create a record, and quick repair protects both your residents and your reserve fund.
Why Cutting the Root Rarely Solves the Problem
Many owners ask us to cut the root causing the problem and then repair the asphalt. This method usually does not work for two reasons. First, cutting the roots harms the tree; the Georgia Urban Forest Council states that damaging roots in the top 12 to 14 inches of clay soil may result in dieback or death, and a weakened tree poses a safety hazard to your residents and their vehicles. The second reason is that researchers at Wageningen found that cut roots produce new roots or shoots, and these new roots can damage the pavement again.
For every tree repair, we employ certified arborists and cut back only what the tree can tolerate. We also don’t repair the asphalt until we’ve addressed the root conditions that caused the damage.
Repair Options We Use
The appropriate solution varies by tree type, soil, and available space.
| Repair approach | Best for | What it involves |
| Remove and replace damaged asphalt | Localized lifting with a manageable root | Saw cut, remove asphalt, rebuild the base, and repave |
| Arborist-guided root pruning | Mature trees with non-structural roots crossing the pavement | Clean cuts by a qualified arborist before we repave |
| Root barrier and enlarged planting island | Trees close to curbs and drive aisles | Install a vertical barrier and give the roots more soil |
| Tree removal and stump grinding | Trees too large, too close, or too unhealthy to save | Remove the tree, grind the stump, and restore the pavement |
It worth looking at barriers. In many cities, root control barriers are required for trees within 8 feet of the pavement, along with a 4-inch perforated pipe. We adopt that standard when the design permits it, since a barrier at the edge of the pavement keeps roots away from the asphalt and lets them grow safely in the soil.
Protect Your Lot Before the Next Ridge Appears
Root damage develops slowly at first but then suddenly happens. A minor ridge this year can become a tripping hazard the following year and then require full-depth repair afterward. We help apartment complexes anticipate that progression by conducting a tree-and-pavement evaluation that maps risk areas, ranks each repair by its impact on safety, and provides a clear budget.
If you contact The Pavement Group right away, you can arrange a lot evaluation; they will show you where your property is headed and will repair your pavement in a manner that safeguards both your asphalt and your trees.
Frequently Asked Questions
Do I need permission before pruning or removing a tree near my parking lot?
You frequently do. Many cities and counties have rules about felling trees, and in some cases trees that exceed a given trunk diameter or are located in the public right-of-way are protected. Approval might be needed from your HOA, according to the terms of your lease, or as specified in the original site plan before any landscape tree is cut down or removed. We advise you to contact your local forestry or planning department and review your community documents before we arrange any tree work. We will then plan the pavement repair in line with the approved scheme to keep the schedule on track.
Does property insurance cover pavement damaged by tree roots?
Coverage varies, so check your policy with your agent. Although many property policies exclude damage that develops gradually—for example, wear and tear, settling, and root growth—liability coverage could apply if a resident makes a claim for injury. In some cases, the way tree-related claims are handled depends on whether the tree caused sudden damage or slow deterioration. Although we are not acting as insurance advisors, we do provide dated photographs, repair scopes, and notes on the cause of failure to help you make a clear claim. Be sure to ask your agent about any exclusions relating to roots and settlement.
When is the best time of year to repair root damage?
In most areas, spring and autumn are the best times of the year. Asphalt needs mild, steady temperatures to compact correctly, and in cold weather the mixture cools too quickly. Working during the dormant season also reduces stress on trees, which is an advantage when an arborist has to prune the roots. Whenever possible, we avoid extensive excavation during periods of extreme heat, drought, or active growth, since stressed trees cannot tolerate root cuts. We then arrange each project based on your local climate, the type of tree you have, and your residents’ parking requirements.
Can we pave directly over exposed roots?
No, and we don’t recommend it. Hot mix asphalt is laid down at high temperatures, and this heat can damage the roots and bark near the surface. The pavement also seals in the soil, cutting off the water and air the roots need to survive. The raised, exposed root keeps pushing against the new asphalt and causes it to crack again. We remove the damaged part, set the correct grade, and then let an arborist decide the best way to protect or redirect the root before laying the new asphalt.
How should we plant new trees so they do not damage the lot later?
Start with the right species and the right distance. Choose smaller, deeper-rooting trees for islands near pavement, and keep large species farther away, since a guide to large trees such as sycamore suggests a setback of 25 to 40 feet from pavement and buildings. Give each tree a planting area that holds enough soil for its mature size, and install a root barrier along the pavement edge. We coordinate with your landscaper during parking lot projects so new trees fit the layout instead of fighting it.
How often should we inspect our trees and pavement for root problems?
Walk the property at least once a year, and add a second walk after a drought or a severe storm. Look for new cracks near planting islands, ridges along curbs, and dips that hold water after rain. Photograph each location and mark it on a site plan, so you can track how fast each problem grows. We offer property evaluations that include this review, and we flag small repairs while they still cost little. A yearly habit keeps minor root damage from turning into a full-depth repair.
See also: What Causes Parking Lot Rutting at an Apartment Complex?, How Do You Repair Asphalt Damage Around Apartment Catch Basins?
