Should I get a written compaction spec for my Ottawa asphalt driveway?

Absolutely yes — a written compaction specification is one of the most important protections you can have for an Ottawa asphalt driveway project. Without proper compaction, your driveway will fail within 2-3 winters regardless of how good the asphalt looks on installation day.

Why Compaction Specs Matter in Ottawa

Ottawa's extreme climate makes proper compaction absolutely critical. With 50+ freeze-thaw cycles per winter and temperatures swinging from -30°C to +35°C, any voids or soft spots in your driveway will become failure points. Poorly compacted asphalt allows water penetration, which freezes, expands, and creates the spider web cracking (alligator cracking) that destroys Ottawa driveways prematurely.

The specification should require minimum 95% compaction density for both the granular base layers and the asphalt surface. For granular base materials (Granular A and Granular B), this means compacting in maximum 150mm lifts with a vibratory plate compactor or roller. For asphalt, it means rolling with a steel drum roller while the mix is still at proper compaction temperature (typically above 80°C for the surface course).

What Your Written Spec Should Include

Your contract should specify that all granular base materials will be compacted to 95% Standard Proctor Density in lifts no thicker than 150mm. The asphalt should be compacted to 95% Marshall Density or 92% of theoretical maximum density. The contractor should also specify the compaction equipment they'll use — hand tamping or single-pass rolling is insufficient for Ottawa conditions.

Include a requirement for nuclear density testing on larger driveways (over 200 square metres) or where soil conditions are questionable. This involves bringing a nuclear density gauge to verify compaction levels have been achieved. While this adds $200-400 to project cost, it's invaluable insurance against base failure that would cost $5,000-12,000 to repair.

Red Flags to Watch For

Be wary of contractors who dismiss compaction specs as "unnecessary for residential work" or claim their experience is sufficient guarantee. In Ottawa's clay soil conditions, even experienced crews can miss soft spots that won't show problems until the first winter. Also avoid contractors who plan to compact granular base in lifts thicker than 200mm — proper compaction cannot be achieved in thick lifts, especially with smaller equipment.

When to Hire a Pro

Any asphalt driveway project requires professional installation with proper compaction equipment. A quality paving contractor will welcome detailed specifications because they protect both you and them from disputes later. If a contractor resists providing written compaction specs, find another contractor — this is non-negotiable for Ottawa driveway longevity.

Need help finding a driveway contractor who understands Ottawa's compaction requirements? Ottawa Driveways can match you with experienced local paving professionals who work to proper specifications.