Should my Vancouver paver contract include a base spec section?

Absolutely yes — the base specification section is the most critical part of any paver contract in Metro Vancouver. A detailed base spec protects you from the most common and costly installation failures, which almost always stem from inadequate base preparation in our wet climate.

Your contract should specify exact base depths, materials, and compaction requirements because these determine whether your pavers will last 5 years or 25+ years. In Metro Vancouver's marine climate with over 1,200mm of annual rainfall, proper base preparation isn't optional — it's the foundation that prevents settling, shifting, and water damage that destroys paver installations.

Essential Base Specifications to Include

Excavation depth should be clearly stated — typically 8-10 inches total depth for patios and walkways (6 inches compacted gravel base plus 2 inches bedding sand), and 12-14 inches for driveways (10 inches compacted gravel base plus 2 inches bedding sand). The contract should specify excavation to "undisturbed native soil" or "engineered subgrade" — not just a depth measurement from existing grade.

Base material specifications must be precise. Specify "3/4-inch minus crushed angular gravel" or "19mm minus road base aggregate" — not just "gravel." The material should meet ASTM D2940 or CSA A23.1 specifications for gradation. Angular crushed rock compacts better and provides superior load-bearing capacity compared to rounded river gravel. The "minus" designation means it includes fines (small particles) that help the material bind together when compacted.

Compaction requirements are critical in Metro Vancouver's clay-heavy soils. Specify "95% Standard Proctor Density achieved through compaction in maximum 2-inch lifts using a minimum 5,000-pound plate compactor." This means the contractor cannot dump 6 inches of gravel and run a compactor over the top once — they must compact in thin layers to achieve proper density throughout the base.

Geotextile fabric should be specified between the subgrade and base material, especially in Surrey, Richmond, Delta, and Langley where clay content is high. Specify "non-woven geotextile separation fabric meeting ASTM D4751 standards" to prevent clay migration into the base over time.

Drainage provisions must be detailed for Metro Vancouver installations. Specify minimum 2% surface slope away from buildings, perforated drain pipe at low points, and connection to storm drainage or dry wells where required. Include provisions for managing roof downspout runoff that might affect the paver area.

What Happens Without Proper Base Specs

Contractors working without detailed specifications often cut corners on base preparation because it's the most expensive and labor-intensive part of the job — but also the part homeowners can't see once pavers are installed. Inadequate base depth saves maybe $2-4 per square foot in material and labor costs upfront, but causes $15-25 per square foot in repair costs within 2-3 years when the installation fails.

In Metro Vancouver's wet climate, insufficient base depth means water saturates the subgrade clay, causing differential settling where some areas sink while others don't. This creates an uneven surface that ponds water, develops trip hazards, and often requires complete reconstruction rather than simple releveling.

Poor compaction is equally destructive but harder to detect until failure occurs. Base material that looks adequate but isn't properly compacted in lifts will settle under traffic loads and seasonal moisture changes. The entire patio or driveway can drop 1-2 inches uniformly, or worse, settle unevenly creating a wavy, unstable surface.

Additional Contract Protections

Include material specifications for edge restraints — aluminum or steel L-channel edge restraints spiked every 2-3 feet into the compacted base. Specify that edge restraints are required on all unconfined edges, including driveway edges that don't abut concrete curbs.

Polymeric sand specifications should require name-brand products (Techniseal, Alliance, Sakrete) rather than generic alternatives that perform poorly in Vancouver's wet conditions. Include proper activation procedures and a requirement to protect pavers from rain for 24 hours after polymeric sand installation.

Warranty terms should be tied to base specifications — a contractor confident in their base preparation should offer 2-3 years warranty against settling or shifting. Be wary of contractors who won't warranty their work or only offer 30-90 day warranties.

Payment schedule should tie payments to completion of base preparation phases — never pay more than 10-20% upfront, with significant payments only after base excavation, compaction, and inspection are complete. This ensures the contractor has incentive to complete the critical but invisible base work properly.

A detailed base specification section transforms your contract from a vague agreement into a technical document that ensures professional-grade installation. Vancouver Interlock can help match you with contractors who understand and welcome detailed base specifications — experienced professionals know that proper base prep protects both the homeowner's investment and their own reputation.