Do contractors need to mill my old driveway before resurfacing it in Ottawa?

Milling is not always required before resurfacing, but in many Ottawa situations it is the difference between an overlay that lasts and one that fails within a few years.

What Milling Is

Milling (also called cold planing or profiling) uses a machine with a rotating drum fitted with carbide teeth to grind away a specified depth of existing asphalt. The milled surface is rough and textured, which provides an excellent bonding surface for the new overlay. The removed material is typically recycled at an asphalt plant.

When Milling Is Necessary

Ottawa contractors will recommend milling when the existing driveway surface has significant issues that would compromise an overlay. These include: extensive surface cracking where water has been infiltrating the asphalt for multiple freeze-thaw seasons; height restrictions where adding a full overlay would raise the driveway above the garage floor, walkway, or drainage structures; and surface irregularities such as ruts, bumps, or areas that have heaved unevenly due to frost.

In neighbourhoods like Stittsville and Manotick built on Leda clay, differential settlement is common. Milling allows the contractor to remove high spots and create a more uniform surface before placing the overlay, resulting in a smoother finished grade.

When Milling Is Not Needed

If your existing driveway is in relatively good structural condition with only surface oxidation, minor hairline cracks, and no height constraints, a contractor can clean the surface, apply a tack coat, and place the overlay directly. This is the most economical approach and works well for driveways that have been maintained with regular sealing and crack filling over the years.

Cost of Milling in Ottawa

Milling adds approximately $2.00 to $4.50 per square foot to the resurfacing project, depending on the depth of material removed and the size of the driveway. For a typical 400 to 500 square foot driveway, expect an additional $800 to $2,250 for milling. The cost includes machine mobilisation, the milling itself, and removal of the milled material (called millings or RAP, which is often reused as granular fill).

Ottawa Climate Factor

One reason milling is more common in Ottawa than in milder climates is the cumulative damage from our winters. After 15 to 20 years of freeze-thaw cycling, road salt exposure, and snowplow contact, the top layer of an Ottawa driveway is often too deteriorated to accept an overlay with confidence. Milling removes that compromised layer and exposes sound asphalt underneath, giving the new surface a solid foundation.

What to Discuss with Your Contractor

Ask whether the milled depth will be uniform or variable (to correct grade issues), whether the millings will be left on-site or hauled away, and how the milling affects the total height of the finished driveway. A contractor who takes the time to assess your specific driveway rather than defaulting to one approach for every job is worth the consultation.

Find experienced resurfacing contractors in your area through Ottawa Driveways and get a proper assessment of whether milling is warranted for your specific driveway.

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

• Luxe Painting and Renovations
• JC Carpentry
• ALM Construction & Landscaping Inc.
• Dump n Dash Hauling
• Home Front Services