Locally quarried natural stone not only creates strong, attractive retaining walls but also offers several economic and construction benefits. Although natural stone generally costs more than precast concrete blocks, locally sourced stones benefit you with reduced transportation costs, and buying from a local quarry supports your area's economy. Building retaining walls with natural stone is relatively easy yet physically demanding. Unlike most core-fill concrete block retaining walls, natural stone retaining walls stack without mortar and accept irregularly shaped stones.
Lay out the position of the retaining wall's sub-base trench on the ground with a tape measure and layout spray paint. Although the length of the wall is variable, the width of the trench must be 6 inches larger than the width of the stone. For example, 12-inch stone requires a 16-inch-wide sub-base.
Pound stakes into the ground at both ends of the trench with a mallet. Run builder's twine between the stakes and tie the twine to the stakes at the height of the first course of stone. The twine serves as a leveling gauge for the first course of stone.
Dig the sub-base trench according to the layout lines; round-nosed shovels scoop large portions of soil from the trenches, and square-nosed shovels square the trenches' edges. Dig the trench to a minimum of 12 inches. Use shovels to fill the trench with drainage gravel to ground level.
Compact the drainage aggregate with a manual tamper. Add additional drainage gravel to the trench to level low spots. Place a stone at the end of the trench on top of the drainage gravel. Align the stone with a string line. Pound the stone to adjust its level; check for level on both sides, front and back. Remember, natural stone will not sit perfectly level.
Place a second stone next to the first. Lay a level across the two stones and use a mallet to adjust the second stone's level until it is roughly equivalent to the first. Continue laying stones along the sub-base trench until you reach the end of the wall.
Lay a second course of stones on top of the first. Set the front of the second course approximately 1 inch behind the face of the first. Do not allow the joints between stones in the second course to overlap the joints between stones in the first course; if necessary, cut stones to length using a stone splitter.
Level the stones in the second course by placing shards of split stones between the second and first course. Drape drainage fabric or weed block fabric over the rear face of the wall, and fill the space between the sloped landscape and the stone with drainage gravel. Lay additional courses, draping fabric and adding drainage gravel every two courses.