Index is a town of 153 people in the Skykomish valley, tucked under steep, rocky walls. Rain comes down those walls in a hurry. Yards are small clearings, and the mountain is the neighbor on every side. Foothill banks want mass. A light stack will walk down the hill the first winter the seep gets behind it.
Snohomish County · ZIP 98256 · 2020 population 153
This is the ground rock walls are for
We use large base stones, a batter back into the hill, and drain rock in the voids so the wall is not holding a lake. The face stone is local and irregular. A cut bank above a drive is structural, and if the height needs an engineer we stop and get one instead of adding another course.
Machine access is the limit. If the driveway cannot take the truck, the wall gets smaller or it gets built from stone we can actually place. We will not design a quarry face we cannot deliver.
The ground in Index
There is no subdivision playbook here. Access can be a single lane, the soil is thin over rock, and a “backyard” may be forty feet of level ground before the timber starts. Intense runoff is the design constraint. A wall has to be heavy enough to stay put, and a drain has to daylight somewhere that does not wash out the next switchback.
We keep planting short and native. Anything that needs summer water and a gardener will lose. Gravel and hardscape earn their place because they stay usable when the ground is soaked. Pruning and cleanup are how you keep the forest from taking the roof, the line of sight on the drive, and the ditch that is supposed to carry the runoff.
How we do the work
A rock wall is dry-stacked or lightly set, with the weight in the stone and the drainage in the voids. It is not a veneer glued to a failing timber wall. We use rock big enough for the height, with a face that leans back into the hill, and smaller rock locked behind so the soil does not pipe through.
Good rock work looks heavier at the bottom. If every stone is the same patio-sized block, it is not a wall, it is a stack. We source local stone and we will tell you when the access cannot take the boulder the job wants.
What we look at first
- Height and whether it is structural or a garden edge
- Machine access for real boulders
- The soil behind: clay that needs a drain, or rock that already sheds
- An existing wall we are tying into
Tying into old rockery
We can often continue an existing rockery if the old base is still honest. If the old wall is tipping, we take it down and use the good stone again. Matching a lean is how you extend a failure.
Dry stack versus mortared
Most of our rock walls are dry, so water can leave and the wall can move a little without cracking a joint. Mortar is for a low, formal edge that is not holding a wet hill. We do not mortar a drainage problem shut.
The base course
The biggest stones, buried, on compacted rock or competent ground. If the first course is the one you can see sitting on the grass, the wall is already failing. You should see the second course at grade, not the bottom of the first.
More from this crew
- Rock walls across Snohomish County
- Retaining walls in Index
- Gravel installation in Index
- Landscaping in Index
- Hardscaping in Index
- Rock walls in Gold Bar
- Rock walls in Sultan
Sources for the climate and the water
- USDA plant hardiness map for choosing plants that can take a Snohomish County winter.
- EPA WaterSense on watering less once a lawn or a new planting is established.
- EPA Soak Up the Rain on keeping roof and yard water from becoming someone else’s problem.
