Hardscaping in Green Lake

Because flat ground has nowhere to shed it and the soil on the low ground near the lake is heavier and wetter than the glacial till through the rest of the neighbourhood. Water that would run off a slope and soak into free-draining material simply sits. The answer is not usually a bigger patio fall — it is a drainage route that takes water somewhere, plus a base built deep enough in free-draining material that it does not turn into a sponge under the paving.

They can be, with a caveat specific to this ground. Permeable paving works by letting water through into a reservoir base and then into the soil beneath — which requires the soil beneath to accept it. On the heavier low ground near the lake, infiltration can be slow enough that a permeable system needs an outflow anyway. On the better-draining ground up toward the ridge they work well. We test rather than assume, because a permeable system over ground that will not take water is an expensive way to build a puddle.

Usually not for structure, often for definition. Flat lots here rarely need retaining walls, but low garden walls and raised beds do a lot of work: they lift planting out of ground that stays wet, they define a patio edge, and raised beds give you soil you control rather than the heavy stuff that came with the lot. That is a different product from a retaining wall and it is priced per linear foot rather than per square foot of face.

Different job entirely, and closer to the rest of hillside Seattle. Real grade means retaining walls or terracing, with drainage behind them built in as the wall goes up. The four-foot permit threshold applies, measured from the bottom of the footing, and terracing into two shorter walls often avoids it while giving you more usable ground. A lot three streets west of the lake can need an approach a lot on the basin never would.