How do I check if my Ottawa driveway base supports a resurface?

Before resurfacing an asphalt driveway in Ottawa, you need to verify that the existing base is structurally sound and stable — overlaying new asphalt over a failed base locks in the problems beneath and leads to rapid failure within 1-2 winters.

Start with a visual inspection of the existing surface. Extensive alligator cracking (interconnected cracks forming a web pattern) indicates base failure beneath the asphalt and rules out resurfacing. Large potholes, significant rutting, or areas where the driveway has sunk also signal base problems. Minor surface cracks, oxidation, and weathering are normal after 15-20 years and don't necessarily indicate base failure.

Test the structural integrity by walking the entire driveway and feeling for soft or spongy areas that flex underfoot. Use a sledgehammer or heavy mallet to strike the surface every few feet — a solid base produces a sharp, solid sound, while a failed base creates a dull thud or hollow sound. Any areas that feel unstable or sound hollow need base repair before resurfacing is viable. Pay special attention to the driveway edges where Ottawa's freeze-thaw cycles cause the most base deterioration.

Check the drainage patterns carefully. Water pooling anywhere on the surface indicates either poor original grading or base settlement that has altered the slope. Ottawa driveways must maintain a minimum 2% slope toward the street or drainage system. Standing water accelerates asphalt deterioration and will quickly damage a new overlay. If water pools, the base may need to be rebuilt to restore proper drainage.

Ottawa's clay soils and extreme freeze-thaw conditions make base evaluation critical. Clay subgrade movement can destabilize the granular base even when the surface looks acceptable. Look for heaving patterns (raised sections) or settlement depressions that indicate the base has shifted. The frost line penetrates 1.2-1.5 metres deep in Ottawa, so base problems often develop gradually over 15-20 years as freeze-thaw cycles work deeper into inadequately prepared foundations.

Professional assessment is recommended for driveways over 15 years old or showing any signs of structural issues. A qualified paving contractor can perform core sampling to check base depth and condition, evaluate subgrade stability, and determine if the existing foundation can support an overlay. Resurfacing over a questionable base saves money upfront but typically requires complete tear-out and replacement within 3-5 years — far more expensive than doing it right the first time.

When resurfacing is viable (stable base, good drainage, only surface-level damage), the existing asphalt should be cleaned, cracks filled with hot-pour sealant, and any loose material removed before applying the new 50mm surface course. The overlay should extend slightly beyond the original edges and be properly compacted while at temperature.

Need help finding a qualified paving contractor to assess your driveway base? Ottawa Driveways can match you with local professionals who understand Ottawa's specific soil and climate challenges.