How to Install Slate Stacking Stone
- 1). Select the slate stones to use for the construction of your stacked stone wall. If possible, they should be as uniformly sized as possible, but include in your selection a number of thin stones that can be used as shims over the course of construction, so the levels of the stone remain relatively even.
- 2). Lay out the first course of stones on the ground where you intend to install the stacked stone wall. A general rule of thumb is, for every foot of height the wall attains, it should have a width of approximately 9 inches. This means a constructed 4-feet-high wall should have a base width approximately 3 feet. The sides of the wall taper slightly up during construction, to center most of the weight of the stones over the middle of the stack, similar to a pyramid.
- 3). Fill the area between the first course of stones with crusher run gravel, then tamp it securely in place with a soil compactor. The crusher run should be perfectly even with the top edge of the first course of stone.
- 4). Install the second course of stone onto the wall in the same manner you installed the first, but push the slate slightly back from the edge of the first course of stone. This produces the desired "pyramid" effect that helps the stacked slate wall retain its shape. At minimum, you should push the stones back from the edge of the lower course of stone 1/8-inch.
- 5). Fill the center of the second course of stone with crusher run gravel, just as you did with the first course, but use care when you tamp the stone down, as you don't want to upset the position of the slate you just added to the wall.
- 6). Add slate and crusher run gravel to the wall, one course at a time, until the wall reaches the height you desire. When you are satisfied with the height of the wall, install a series of heavy cap stones onto the top course of slate to help prevent rain from washing away the dust of the crusher run gravel. Over time, this washes away anyway, but by the time this occurs, the wall will have settled into the soil, and the slate stones will be mostly locked in place.
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