How to Install Large Landscape Blocks

Measure the area you want to cover with your landscaping blocks. Use this measurement to determine how many blocks to purchase for your project. Outline your selected area with garden stakes and string, marking off the length and width of the intended structure. This temporary guide will provide a visual border that keeps your wall or border in alignment with your plans.

Remove the sod or groundcover from your selected site. Use a shovel to dig to a depth equal to the height of a single block plus 5 to 7 inches. Add soil to bring up shallow areas and scoop away soil to remove lumps, creating a level surface along the bottom of your trench. Use a tamp to compress the soil.

Pour a 4- to 6-inch layer of crushed rock into your trench. Spread the rock evenly with a shovel. Compact the layer of rock with the tamp. Pour a 1-inch layer of coarse sand over the top of your crushed rocks. Tamp once more to firm the sand and rock.

Set your first row of large blocks into your prepared trench. Press each block firmly against the others to avoid gaps and cracks. Use a long carpenter's level to ensure a uniform height along the tops of the blocks. Level the blocks by lifting high ones and removing excess fill, while adding additional amounts under blocks that sit lower than the rest. Once your blocks are level, tamp them in place with a heavy rubber mallet. Fill in any gaps around your stones by scooping some of the removed backfill into any exposed areas of the trench.

Place the second layer of large stones over the bottom layer. Make your structure as sturdy as possible by setting the second row of blocks so the joints are at alternating positions from the underlying layer.