How To Install Retaining Walls With Natural Stone

Steep slopes and small cliffs of dirt on your property often erode under excessive rainfall, leaving mud and rock on paths, lawns and driveways. Building retaining walls prevents this soil erosion and helps disguise the unattractive remains from excavation into a hillside. Homeowners may build their own retaining walls from natural stone without using mortar and adhesives and with careful attention to detail.

Step 1

Excavate a trench in front of the hillside where you wish to place the retaining wall. Cut into the existing slope to create a trench at least 2 feet wide and 4 inches deep in front of the hillside or dirt cliff.

Step 2

Level and compact the base of the trench. Check the length and width of the trench bottom with a level and remove high points to create a perfectly level wall base. Compact the soil to create a sturdy foundation by repeatedly pounding the soil tamper against the base until the soil resists further compaction.

Step 3

Fill the trench with a 3-inch layer of gravel to promote drainage under the wall and provide a firm base. Level and compact the layer of gravel using the level and soil tamper.

Step 4

Lay the largest stones you have into the trench first to create the first course of the wall. Take time to position rocks to minimize the gaps in between and choose rocks of similar thicknesses, filling the front 1 1/2 feet of the trench.

Step 5

Fill gaps between stones with smaller rock, gravel and soil misplaced from excavating the trench. Shovel the filler material into the caps and use the soil tamper to compact the material into the gaps. Apply a 1/2 layer of soil and filler on top of the first course of stone and compact the layer.

Step 6

Apply additional layers of stone one at a time, fitting stones together to reduce gap sizes to between 1/2 and 1 inch wide. Fill gaps with soil and smaller gravel, apply a thin top layer and compact the soil before applying the next layer. Choose smaller widths of stone for each layer and scoot the stones back from the previous layer to create a batter or backwards slope on the front of the wall. Continue to add layers as necessary without exceeding 5 feet in height.

Step 7

Install a perforated plastic pipe behind the finished retaining wall to direct draining water away from the retaining wall to prevent the wall from falling under excessive rainfall. Cover the pipe with crushed stone and gravel, leaving 6 inches between the gravel layer and the top of the retaining walls. Fill the remainder of space at the top of the wall with soil.