40mm washed rock is clean, consistent, and built for Calgary's toughest drainage and landscaping applications. The washing process removes clay, dust, and fine debris — leaving a rock that drains freely, looks clean in a yard, and performs reliably in both structural and decorative applications. The 40mm sizing creates generous void space between rocks for fast water movement, making it one of the most effective drainage materials we carry.
What it's used for
- Drainage systems and French drains — the clean, washed surface prevents fine particles from clogging the void space between rocks, keeping drainage systems flowing freely for years
- Foundation and footing drainage — placed around foundations to move water away from the structure quickly and prevent hydrostatic pressure
- Retaining wall backfill — the large void space allows water to drain freely behind walls without building up pressure
- Concrete and asphalt base — used as aggregate in concrete mixes and as a stable sub-base layer for roads and paved surfaces
- Decorative garden beds and ground cover — the washed surface gives a cleaner, brighter appearance than unwashed rock, making it a popular decorative choice for open beds and borders
- Pathways and driveways — large enough to stay in place under foot and vehicle traffic, with a cleaner look than standard crush
- Dry creek beds and water features — the washed finish looks natural and holds up well around water
Washed rock vs drain rock — what's the difference?
Both are 40mm angular rocks used for drainage, but washed rock has been cleaned of fines and clay particles. This makes it better for applications where drainage performance needs to stay consistent over time — clogging is the enemy of any French drain system, and washed rock resists it better than unwashed material. If drainage is your primary goal, washed rock is the better investment.
How much do you need?
For a 4-inch drainage 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