Riprap and erosion control installation typically costs $40 to $100 per ton of stone placed, or $15 to $40 per square foot of protected area including grading and filter fabric, depending on rock size, slope, and site access. Treat every figure on this page as a starting point rather than a quote: riprap sizing is an engineering decision based on expected water velocity and slope, not an aesthetic one, and undersized rock simply washes away in the next significant flow event.
Riprap is placed along shorelines, streambanks, ditches, and slopes to absorb the energy of moving water and prevent the underlying soil from eroding away. The rock size needed depends directly on how fast and how forcefully water moves across that particular site during peak flow, which is why a one-size answer for riprap sizing doesn't hold up across different locations.
What actually drives the price
Rock size and gradation are set by expected water velocity at the site. A slow-moving drainage ditch needs smaller stone than an area exposed to storm surge, fast stream currents, or wave action on a shoreline. Larger rock costs more per ton and is harder to place, but undersized rock is not a place to save money since it fails under the exact conditions it's meant to resist.
Slope grading before rock placement affects both cost and performance. The underlying slope typically needs to be graded to a stable angle and often lined with filter fabric before riprap goes down, since the fabric prevents the underlying soil from washing out through the gaps between rocks even after the rock layer itself holds.
Access to the site matters significantly for cost, since riprap is heavy and placing it along a shoreline, streambank, or steep slope sometimes requires specialized equipment or careful sequencing to avoid disturbing the bank further during construction.
Area and depth of coverage scale cost directly through total tonnage required, but the depth of the rock layer itself is also an engineering specification, not a visual judgment call, and needs to match what the site's exposure actually requires.
Permits near water
Work along a shoreline, streambank, or within a regulated floodplain typically requires a permit from a conservation authority or environmental regulator, since this work directly affects a water body or its buffer zone. Confirm this requirement before scheduling, since unpermitted work near water is often subject to enforcement action.
A short checklist before you book
Confirm expected water velocity or flow conditions to size the rock correctly. Ask whether filter fabric will be installed beneath the riprap layer. Confirm site access and how equipment will reach the work area without disturbing the bank. Check permit requirements if the work is near a shoreline, stream, or floodplain. Confirm coverage depth matches the site's actual exposure, not just a standard default.
Costs vary by site conditions. Use the ranges here to sanity-check what you're quoted, then get a direct price for your own property. If your project needs riprap or armor stone, Natural Stone Source Ontario can help with supply.
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