Should I pick HL3 or HL4 asphalt for my Ottawa driveway?

For residential driveways in Ottawa, HL3 is the standard choice and what most paving contractors will recommend and quote. HL4 is a finer, premium mix typically reserved for high-end applications, airport runways, or specialized projects where the extra cost is justified.

HL3 (19mm maximum aggregate size) is specifically designed for residential driveways and provides excellent durability for Ottawa's freeze-thaw conditions. The aggregate gradation gives good compaction characteristics and creates a surface that's smooth enough for comfortable walking and vehicle traffic while providing adequate texture for traction. HL3 handles the thermal expansion and contraction from Ottawa's 60-degree temperature swings between winter and summer, and the aggregate size is optimal for the typical 50mm lift thickness used in residential paving.

HL4 (12.5mm maximum aggregate size) uses smaller aggregate and creates a finer, smoother surface finish. While this sounds appealing, it comes with drawbacks for Ottawa driveways. The smaller aggregate size makes HL4 more susceptible to rutting under heavy loads, and the finer texture can become slippery when wet or icy. HL4 also costs 15 to 25 percent more than HL3 but doesn't provide meaningful performance benefits for residential use in Ottawa's climate.

Ottawa's extreme freeze-thaw cycles — over 50 per winter — are hard on any asphalt mix. HL3's aggregate gradation and binder content are specifically formulated to handle this stress. The key to longevity isn't the asphalt grade but proper base preparation (minimum 300mm Granular B sub-base plus 150mm Granular A base in Ottawa) and regular sealcoating every 2 to 3 years to prevent water infiltration.

Most Ottawa paving contractors stock and recommend HL3 because it's the industry standard for residential work. Unless you have specific requirements for an ultra-smooth surface (rare for driveways), HL3 provides the best balance of performance, durability, and cost. Focus your attention on finding a contractor who won't cut corners on base depth and compaction — that's far more important than the asphalt grade for long-term performance.

When to consider HL4: Only if you're doing a high-end project where appearance is critical and cost isn't a concern, or if your contractor specifically recommends it for technical reasons related to your specific site conditions.

Need help finding a paving contractor who understands proper Ottawa driveway construction? Ottawa Driveways can match you with local professionals for free estimates.