Flagstone calculator

100 sq ft of 1.5 in stone: 1 ton.

Cuts and a stone that breaks. The chart is already an approximate laid coverage.

Job sheet

Plumb flagstone job sheet

100 sq ft per ton, 0% for cuts.

  • Tons1 tons100 sq ft to cover. 2,100 lb at 21 lb/sq ft.
Plumb flagstone job sheet
100 sq ft per ton, 0% for cuts.

Tons: 1 tons (100 sq ft to cover. 2,100 lb at 21 lb/sq ft.)

Tons from the coverage chart

Tons are the patio, plus waste, divided by the square feet per ton for that thickness. One hundred square feet at 1.5 inches is one ton on this chart, and 2,100 pounds, because the same row is 21 pounds per square foot. A 2 inch patio of the same size is 1.25 tons. Bedding sand under the stone is sand. Gravel for a deeper base is gravel. Large erosion stone is rip rap.

FAQ

How many tons of flagstone for 100 square feet?

At 1.5 inches the chart is 100 square feet per ton and 21 pounds per square foot, so 100 square feet is 1 ton and 2,100 pounds. At 2 inches the same chart is 80 square feet per ton. At 1 inch it is 150. Cuts and broken stones are the waste percent, which starts at 0.

Why not count the pieces?

Flagstone is irregular. A quarry sells it by the ton and prints square feet per ton for a thickness. A joint you leave open is already inside that laid coverage. A patio of cut rectangles with a measured joint is the paver page, not this one.

Is every limestone the same weight?

No. The chart this page uses is Ontario limestone at 165 pounds per cubic foot. Indiana limestone on the same sheet is 145, and the granite line is 175. If the yard prints a different coverage, type that square-feet-per-ton figure by picking the closest thickness and then adjusting the waste, or use the river-rock page and type their pounds per yard.

Sources

  1. Select Stone Supply, approximate coverage guide (30 July 2019): Flagstone, Ontario limestone: 1 in is 14 lb/sq ft and 150 sq ft/ton; 1.5 in is 21 lb and 100 sq ft/ton; 2 in is 28 lb and 80 sq ft/ton.