How Much Crushed Granite Do I Need for a Brick Patio?
- To calculate the amount of crushed granite needed for the foundation, measure the length and width of the site with a measuring tape. Also measure the width of your edge restraints and add this amount to each side so the gravel foundation extends below the edging. Multiply the total width and total length to find the square footage.
- The crushed granite foundation for a patio should be 3 to 6 inches deep. If the area has poor drainage or you expect to transport heavy equipment over the pavement, opt for a thicker base for extra support. Because a 6-inch base is half of 1 foot, multiply the square footage by .5 to calculate the amount of crushed granite needed in cubic feet.
- Crushed rocks are typically sold in cubic yards. Convert the amount of crushed granite from cubic feet to cubic yards by dividing by 27. Account for potential spillage or slight adjustments in the size by adding 5 percent to the total amount. For example, for a 10-by-10-foot patio with a 6-inch-thick base, order 1.95 cubic yards of crushed granite.
- In addition to crushed rocks, you need a bed of coarse grit sand. Sharp particles of sand create traction beneath the bricks that secure them in place. The sand bed should be 1 to 1 1/2 inches thick, but a portion of the sand will naturally fall through the narrow cracks between rocks.
