My asphalt driveway has tree root bumps pushing up through the surface in Stittsville — what are my options?

Tree root damage is a frustrating problem for Stittsville homeowners, especially in older neighbourhoods where mature maples, oaks, and silver birches have had decades to spread their root systems under driveways. The good news is there are several repair approaches, but each involves trade-offs.

Understanding the Problem

Tree roots grow toward moisture and nutrients, and the area beneath a driveway often retains moisture longer than surrounding soil — making it attractive to roots. As roots thicken over the years, they push upward against the granular base and asphalt surface, creating humps, cracks, and eventually breaking through. In Stittsville and western Ottawa, the mature tree canopy means this is an extremely common issue.

Option 1: Root Pruning and Driveway Repair

The most common approach is to excavate the affected area, prune the offending roots, and rebuild the driveway section. This involves sawcutting around the damaged area, removing the asphalt and base material, cutting the roots cleanly with a sharp saw (never an axe — ragged cuts invite disease), backfilling with Granular A, and repaving.

Important caution: Removing major structural roots can destabilize or kill the tree. As a general rule, do not cut roots thicker than 75 mm (3 inches) or roots within the tree's critical root zone (a circle with a radius equal to the trunk diameter multiplied by 12). If the root causing the damage is a major structural root, consult a certified arborist before cutting. The City of Ottawa also has a tree protection bylaw that may apply if the tree is on city property or in certain zones.

Option 2: Root Bridge / Ramp Over the Roots

Instead of cutting the roots, the driveway can be rebuilt to accommodate them. The contractor excavates around the roots, installs a rigid base (sometimes a concrete pad or heavy steel plate) that spans over the root zone, and paves on top. This preserves the tree but adds cost and may create a slight grade change.

Option 3: Root Barrier Installation

After pruning and repairing, a root barrier — a rigid plastic or geotextile sheet installed vertically to a depth of 450–600 mm along the driveway edge — prevents roots from growing back under the driveway. This adds $300–$800 to the repair cost but significantly reduces the chance of recurrence.

Option 4: Reroute or Narrow the Driveway

In some cases, especially with large mature trees, the most practical long-term solution is to slightly adjust the driveway alignment to avoid the root zone entirely. This is a bigger project but eliminates the ongoing battle.

Cost Expectations in Ottawa

Root pruning with driveway patching for a single affected area typically runs $1,200–$3,500 in Stittsville and western Ottawa. Adding a root barrier increases the total to $1,500–$4,300. If the tree needs to be removed entirely (last resort), tree removal in Ottawa ranges from $800–$3,000 depending on size and access, plus the driveway repair cost.

City of Ottawa Considerations

If the tree causing the damage is a city-owned street tree, contact 311 before doing any work. The City may be responsible for the tree management, though they typically do not pay for private driveway repairs. If it is your tree and it is a designated heritage tree or in a mature neighbourhood overlay zone, additional rules may apply.

Connect with a contractor through Ottawa Driveways who has experience dealing with root damage in Stittsville's mature neighbourhoods and can coordinate with an arborist if needed.

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Looking for experienced contractors? The Ottawa Construction Network connects Ottawa homeowners with qualified professionals:

• Homeupgraders
• RenoMotion Inc.
• Geerts Roofing Inc
• The Fixer
• Best Hand2Hand moving company