courses were buried beneath a berm of compacted earth to help hold it in place along the slope. The sidewalk border shown won’t retain a great deal of earth and water. In fact, once completed the sidewalk’s paver surface will shed much of the runoff and rainwater. Taller retaining walls that hold more earth are a differ- ent story however, and accumulat- ed water will add weight and hydrostatic pressure that pushes outward against the wall. Therefore, taller walls require better drainage (see sidebar). SHAPING THE STONE Working with natural stone means dealing with irregularly shaped building materials. Unlike manufactured block which neatly stacks and interlocks, natural stone takes a lot more persuasion when assembling a wall. The installer needs the ability to envi- sion the wall as a whole and the individual pieces he needs to make the wall, and then they need to cre- ate the shapes they need when they’re not readily available. Working with stone might require digging out the trench beneath the first course to set a rock that has an uneven bottom surface. You might need to use a hammer to
Small rocks serve as chinking to fill gaps and solidify the wall.
Stakes and string can be used to guide the wall’s layout and estab- lish elevation.
The upper end of this sidewalk transitions into a level patio area, so as the border wall progresses uphill, fewer courses are used so the bottom of the wall disappears gradually into the ground.
Since water always moves downhill through the path of least resistance, you need to design a path of least resistance that protects your walls and inhibits erosion of your landscaping. You can give the water an easier way out than through your wall by divert- ing it through flexible perforated drainpipe. Along the uphill side of the wall location, dig a trench and slope it downhill to where you want the water to go. Then, build the wall as usual. Line the trench with landscaping cloth and drape it up the slope. Lay the pipe with its holes pointed down, toward the back of the trench. Fill around the pipe with gravel, then fold the cloth over the gravel and cover with dirt.
BETTER DRAINAGE FOR YOUR LANDSCAPE