Setting the Footing for a Dry-Stack Retaining Wall
A flat, compacted gravel foundation is the first thing you need to build a high-quality wall.
You can’t build a solid wall without a sturdy base. Follow these steps to get off to a good start before placing your first wall stones.
Set the footing for a retaining wall 8 in. below grade on compacted soil. Dig the footing trench 3 in. wider than the bottom of the wall 1 and compact the soil with a hand tamper 2. If you have to dig down deeper to reach undisturbed soil in any one area, compact the low spot, fill it with clean gravel, and then compact the gravel 3.
Lay landscape fabric or filter fabric across the bottom of the trench and over the embankment 4. Lay any extra filter fabric on top of the bank and secure it temporarily with stones 5. Later, it will be folded under the capstones; wait until then to cut off the excess.
Lay rocks on the filter fabric to form a footing 6. Bigger stones salvaged from the original wall can serve that purpose. If you are using new stones, choose large ones that would be difficult to shape. Spread gravel between the footing stones, and settle the stones by rapping them with a small sledgehammer or mallet 7. Tamp the entire footing area to lock the stones and gravel in place 8.
Excerpted from Masonry Complete (The Taunton Press, 2012) by Cody Macfie
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