Sloped lots are normal on the Kitsap Peninsula, and retaining walls are how you get a flat lawn, a usable patio, or a driveway that doesn't slide into the road. But a retaining wall is really a drainage project with some blocks on the front, and that's where most of them go wrong.
Water is the enemy. Clay soil behind a wall soaks up months of rain, gets heavy, and pushes. A wall built without drainage is holding back a slope of wet mud, and eventually it bulges, tilts, or lets go. Every wall we build gets a gravel backfill zone, a perforated drain pipe at the base running to daylight, and filter fabric to keep the gravel from silting up.
The base matters just as much. Blocks set on dirt settle unevenly and the wall follows. A compacted crushed-rock base, with the first course buried below grade, keeps the wall level and locked in. For walls over about three feet, geogrid reinforcement layered into the backfill ties the wall to the hillside behind it.
Material choice is mostly about look and budget. Concrete block walls are the workhorse: strong, clean-lined, and quick to build. Natural rock walls suit wooded and waterfront lots. Timber walls are cheaper up front but have a shorter life in our climate. Whichever you pick, the drainage and base rules don't change.
One more thing: walls over four feet, or walls holding up a driveway or structure, usually need an engineer and a permit. We'll tell you up front if your project crosses that line, and what it means for the plan.