What's the best base material for a patio in the Lower Mainland's wet soil?

For Metro Vancouver's wet climate and clay-heavy soils, use 3/4-inch minus crushed gravel (also called road base or crusher run) at a minimum depth of 6-8 inches for patios, with proper drainage design being absolutely critical.

The persistent rainfall and high humidity in Metro Vancouver — over 1,200mm annually with 70% falling between October and March — makes drainage the single most important engineering consideration for any paver installation. Unlike drier climates where base preparation focuses primarily on load-bearing capacity, Vancouver's wet conditions mean water must be able to drain through or away from your patio efficiently, or the base will become saturated and fail.

3/4-inch minus crushed gravel is the gold standard base material because it contains a blend of stone sizes from 3/4-inch down to fine particles that compact together into a stable, load-bearing surface while still maintaining drainage capacity. The angular edges of crushed stone interlock better than rounded river gravel, creating superior stability. Popular local suppliers like Burnco, Lehigh Hanson, and Fraser Valley Aggregates stock this material specifically for hardscape applications.

Base depth is critical — 6 inches minimum for patios and walkways, 8 inches if you have clay subgrade (common in Surrey, Richmond, Delta, and Langley). Clay soil doesn't drain well and can migrate upward into your gravel base over time, destroying its drainage capacity. Always install geotextile separation fabric between clay subgrade and your gravel base to prevent this contamination.

Proper installation requires compaction in lifts — never dump 6-8 inches of gravel and compact it all at once. Spread 2-inch lifts, compact each one with a plate compactor, then add the next lift. This achieves the 95%+ compaction needed to prevent settling. The base must also slope away from your house at minimum 2% grade (1/4 inch per foot) to shed water effectively.

Consider drainage infrastructure for larger patios or areas with poor natural drainage. Install perforated drain pipe at low points, surrounded by clear drain rock, with an outlet to daylight or connection to your storm drain where permitted by your municipality.

Hire a professional for patio installations over 100 square feet — proper excavation, base preparation, and compaction require specialized equipment and experience. Poor base work is the number one cause of paver failure, and it's expensive to fix once pavers are installed on top.

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