How much river rock for a 3 ft strip along the house?
A 3 × 40 ft strip of river rock 3 inches deep needs about 1.58 tons of 1–3 in stone, or 1.17 cubic yards (32 cubic feet), including a 5% allowance.
How to work it out
- 40 ft × 3 ft = 120 sq ft
- 120 sq ft × 3 in ÷ 12 = 30 cu ft ÷ 27 = 1.11 cu yd
- 1.11 cu yd compacted × 1 = 1.11 cu yd loose × 1.35 tons/cu yd = 1.5 tons
- + 5% waste = 1.58 tons
- Effective rate: ≈ 1.42 tons per cu yd compacted
- Bulk: 1.58 tons rounded up to the next ½ ton = 2 tons
Rock along a foundation is popular because it doesn’t hold moisture against the house the way mulch can, and it stops rain splashing mud onto the siding. Forty feet is roughly one side of a small house, or the front wall of a larger one. The ground under the rock still has to slope away from the house; rock on top of a negative grade just hides the problem.
Adjust for your project
More options: Compaction · Waste · Price …
- Loose volume (as delivered)
- 1.17 cu yd (31.5 cu ft)
- Landscape fabric (with 10% for overlaps)
- 132 sq ft
- Coverage per ton at this depth
- 80 sq ft per ton
- Bulk order (rounded up)
- 2 tons (sold by the half ton)
River rock for a 40 ft border, 3 in deep, by strip width
| Width | River rock to order | Loose volume (as delivered) | Landscape fabric (with 10% for overlaps) |
|---|---|---|---|
| 2 ft | 1.05 tons | 0.78 cu yd | 88 sq ft |
| 3 ft | 1.58 tons | 1.17 cu yd | 132 sq ft |
| 4 ft | 2.1 tons | 1.56 cu yd | 176 sq ft |
| 5 ft | 2.63 tons | 1.94 cu yd | 220 sq ft |
What to know about a 3×40 ft river rock border
Just over a ton and a half is the awkward size: about 63 bags of 0.5 cu ft is a lot of carrying, but many landscape yards will load a ton and a half into a pickup (check your payload first) or drop it on the driveway for a delivery fee. Lay a tarp where it lands — rock is hard to rake off a lawn.
Before any stone goes down, fix the grade. Rake the soil so it falls away from the wall along the whole 40 ft, then lay heavy fabric: 132 sq ft with overlaps, pinned every few feet. Tuck the fabric up against the foundation and stop the rock a few inches below any wood siding or weep holes.
Three feet is wide enough to catch roof drip on most single-storey houses. If a gutter downspout empties into the strip, add a splash block or run a drain out beyond it, or the water will wash the rock away in the first storm.
In hot, sunny spots, remember rock soaks up heat; shrubs planted in the strip may need more water than they would under wood mulch. For a runoff channel instead of a border, see how much river rock for a 3×25 ft dry creek bed.
Different size? Use the full River Rock Calculator.
What you’ll need
- Landscape fabric (woven or heavy non-woven)Budget price
Separates stone from soil under gravel and rock. Less useful under wood mulch, which breaks down into soil on top of it anyway.
See options on Amazon (opens in a new tab) - Landscape fabric staplesBudget price
Pins fabric and edging down. Budget roughly one every few feet along seams and edges.
See options on Amazon (opens in a new tab) - Heavy-duty tarpBudget price
Put it down where the truck dumps: it protects the driveway and makes the last shovelfuls easy to scoop up.
See options on Amazon (opens in a new tab)
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Frequently asked questions
How much river rock for a 2×40 ft strip by the house?
About 1.05 tons (0.78 cubic yards) of 1–3 in rock at 3 inches deep with 5% extra, or 42 bags of 0.5 cu ft.
How much small river rock for a 3×40 ft border 2 inches deep?
About 1.05 tons (0.78 cubic yards) of ¾–1½ in rock with 5% extra. Two inches is enough to cover fabric with small stone.
Other common sizes
- How much river rock for a 3×25 ft dry creek bed — 1.31 tons
Sources
- University of Nevada, Reno Extension — Mulches for Nevada Landscapes (opens in a new tab) — Landscape fabric under about 2 in of rock; rock mulches raise soil and air temperature
- Colorado State University Extension — Mulching (opens in a new tab) — Gravel mulch transfers more heat to the soil than wood chips
- Gravel Monkey — How many tons of gravel in a dump truck? (opens in a new tab) — Typical payloads: single-axle about 6–10 tons, tandem 12–16, tri-axle 18–25; gravel hits the weight limit before the bed is full.