Can I pour a concrete driveway over an existing asphalt driveway in NB?

Pouring concrete over an existing asphalt driveway in New Brunswick is technically possible but generally not recommended by experienced NB contractors — the added height, bonding issues, and unpredictable behaviour of the existing asphalt under NB freeze-thaw conditions create problems that outweigh the savings of skipping removal. In most cases, removing the old asphalt produces a better, longer-lasting result.

Why it is appealing: Avoiding asphalt removal saves $2-$5 per square foot in demolition and disposal costs — on a 500 sq ft driveway, that is $1,000-$2,500. Some contractors market this approach as an overlay or bonded slab.

The problems in NB conditions:

Height and grade issues. Adding 5-6 inches of concrete on top of your existing asphalt raises the driveway surface, which can create problems at garage thresholds, sidewalks, and the street approach. In Moncton, Fredericton, and Saint John, many homes already have tight clearances at the garage door that a concrete overlay would completely eliminate.

Bonding is unreliable. Fresh concrete does not bond predictably to aged asphalt. The asphalt flexes under vehicle loads while concrete is rigid — they move independently, especially during NB's freeze-thaw cycles. This differential movement causes the concrete to crack at the interface and eventually delaminate, creating a worse surface than you started with.

The asphalt base is an unknown. Aged asphalt in NB may have soft spots, cracked sections, depressions, and areas where the gravel base has failed. Covering these problems with concrete locks them in — they will telegraph through and cause the concrete overlay to fail at the same locations.

Reduced effective thickness. A concrete overlay must still achieve the full 5-6 inch thickness to perform properly. Pouring thinner concrete because the asphalt provides some base is a compromise that typically leads to premature cracking.

When overlaying can work: If the existing asphalt is in excellent condition, perfectly flat, and the grade and height changes are manageable, a concrete overlay can work. The asphalt must be milled or scarified for bonding, and a proper bonding agent must be applied. This is the exception, not the rule.

The industry-recommended approach in NB is to remove the existing asphalt entirely, inspect and regrade the granular base (adding material as needed to achieve 6-8 inches of compacted base), and pour fresh concrete. This gives you a driveway that will serve you for 30-40 years without the compromises of an overlay. New Brunswick Concrete can connect you with driveway contractors who can assess your specific situation and provide an honest recommendation.