20mm washed rock is one of our most versatile materials — clean, consistent, and the right size for a wide range of Calgary landscaping and drainage projects. The ¾ inch sizing is a Calgary standard — it's what most contractors specify for drainage, what most homeowners reach for on driveways, and what works across more applications than any other single rock size we carry. If you're not sure what size to order, 20mm washed rock is usually the right answer.
What it's used for
- Driveways and parking pads — the most popular driveway rock size in Calgary. Compacts well, handles vehicle traffic, and gives a clean, finished appearance
- Pathways and walkways — easy to spread, stays in place underfoot, and looks natural alongside garden beds and lawn edges
- French drains and drainage systems — the washed surface keeps void space open and water flowing freely, without clogging over time
- Retaining wall backfill — allows water to drain freely behind walls, reducing hydrostatic pressure and extending wall life
- Garden beds and decorative ground cover — cleaner and brighter than unwashed rock, the washed finish gives beds a polished, maintained look year-round
- Concrete aggregate — the consistent ¾ inch sizing is a standard concrete mix aggregate for slabs, footings, and structural pours
- Base material under pavers and flagstone — used as a free-draining sub-base layer before bedding sand and surface installation
- Erosion control — placed on slopes, banks, and bare soil areas to prevent washout during Calgary's spring melt and heavy rain events
20mm washed vs 40mm washed — which size do you need?
The 20mm size is more versatile and works in tighter spaces — better for pathways, decorative beds, and standard driveways. The 40mm size has more void space between rocks — better for heavy drainage applications and larger open areas. When in doubt, 20mm is the safer all-purpose choice.
How much do you need?
For a 4-inch driveway layer, budget roughly 1.2 cubic yards per 100 square feet. Use our free calculator for an exact number.
Where we deliver
Same-day bulk delivery across Calgary, Airdrie, Chestermere, Cochrane, Okotoks, and Langdon.
📞 403-510-9011