Excavation and site work sits at the beginning of most construction projects — and it's the part that homeowners think about least. By the time the visible work is done and the project moves to framing or finishing, what happened at the ground level is buried and invisible. That invisibility is exactly why it matters so much.
What Site Work Includes
Site work and excavation cover a range of ground-level construction activities. Depending on the project, site work might include: site clearing (removing vegetation, topsoil, and debris — on the North Shore this often involves tree removal, stump grinding, and dealing with root systems); excavation (moving soil and rock to create a depression for a foundation, footing, or below-grade structure); grading (reshaping the ground surface to achieve a specific finished elevation and slope — one of the most consequential early decisions in any project); trenching; drainage installation; compaction (mechanically compacting disturbed soil or placed fill to achieve the density needed for stable support); footing excavation and preparation; rock breaking (common on hillside North Shore properties where rock is near the surface); and backfill and compaction after structures are installed.
Footing Depth and Frost Heave
Every footing must extend below the local frost depth to prevent frost heave. On the North Shore, frost depth is generally 18–24 inches. Footings at or near grade move seasonally with the freeze-thaw cycle. A deck whose footings are above frost depth will develop uneven movement over several years — posts lift by different amounts, the deck surface racks, connections loosen. The deck that looked level when it was built tilts and warps. The fix is rebuilding the footings properly — which means demolishing and rebuilding.
Grading and Drainage
How the ground is shaped determines how water moves across the site. Ground that slopes toward the house foundation — even slightly — directs rainfall and snowmelt toward the structure. Over time, this produces moisture intrusion in below-grade spaces and deterioration of the foundation at grade. Proper grading establishes a positive slope away from the house in all directions. Grading that was correct at installation can be undermined by landscaping additions over time — mulch and garden beds built up against the house over years of landscaping, slowly reversing the drainage slope at the foundation.
Compaction and Settlement
Soil that has been disturbed is less dense than undisturbed soil. When a structure is built on disturbed soil that wasn't properly compacted, the soil settles over time. The result is uneven settlement — some areas settle more than others. Patios crack. Driveways develop depressions. Retaining walls tilt. Steps pull away from the structure they're connected to. Proper compaction — achieved mechanically, in layers (lifts), with the right moisture content in the soil — is the difference between a patio that stays flat and one that heaves and cracks within five years.
Drainage System Longevity
Drainage systems installed during site work are buried and essentially inaccessible after the project is complete. A drainage system installed correctly and with the right materials will perform for decades. One installed as a shortcut will fail in a few years, and accessing it for repair means excavating again. The details that matter: aggregate type (open-graded crushed rock, not pea gravel), filter fabric wrapping, proper slope to outlet, and a discharge point that actually works.
What Proper Execution Looks Like
Before any excavation begins: existing site conditions should be assessed — drainage patterns, soil type, presence of rock, location of underground utilities. In BC, calling BC One Call (1-800-474-6886) before excavating is a legal requirement. On sloped properties, geotechnical conditions should be understood before significant excavation. During excavation: excavated material needs somewhere to go, planned before the first shovel goes in. Rock encountered during excavation affects scope significantly — this is a legitimate unknown on many North Shore projects and one of the reasons site work is often priced cost-plus. After excavation: backfill should be placed in lifts — typically 150–200mm — and mechanically compacted before the next lift is placed.
Site Work on the North Shore: Specific Considerations
Steep sites require careful attention to slope stability — cut slopes have limits, and excavation that undermines adjacent soil creates risk. Shallow rock is common throughout the hillside areas — finding rock that requires breaking adds time and cost, a known unknown on many North Shore projects. High water tables in lower-lying areas may require dewatering during construction. Older neighbourhoods can have complex and sometimes poorly documented underground utility infrastructure — utilities should always be located before excavation, and on older properties, the actual locations may vary from what's on record.
Frequently Asked Questions
What does excavation and site work include?
Site clearing (vegetation, topsoil, often tree and stump removal), excavation for foundations and footings, grading, drainage installation, and compaction — the ground-level work the rest of the project depends on.
Why does footing depth matter?
Every footing must extend below the local frost depth — generally 18–24 inches on the North Shore — to prevent frost heave. Footings at or near grade move with the freeze-thaw cycle, racking structures and loosening connections over several years.
What has to happen before digging in BC?
Site conditions should be assessed — drainage, soil type, rock, utilities — and calling BC One Call (1-800-474-6886) before excavating is a legal requirement. On sloped properties, geotechnical conditions should be understood first.
What North Shore site conditions affect excavation?
Steep sites need attention to slope stability, shallow rock is common in hillside areas and adds time and cost when it must be broken, and high water tables in lower areas may require dewatering during construction.