Boulder and rock retaining walls
Natural stone suits the pines, lakes and rocky slopes of North Idaho. Get it placed by someone who knows how to make it hold.
Boulder walls use large natural stones, set with heavy equipment, to hold back soil and shape a slope. They're popular around Coeur d'Alene for shorter walls, terraces and lakefront landscaping because they look like part of the landscape. Done well, a boulder wall is stable, drains naturally and needs little upkeep.
When is a boulder wall a good choice?
- Shorter walls and terraces on gentle to moderate slopes
- Natural-looking landscapes, cabins and lake properties
- Sites where the builder can get an excavator in to place stone
- Edging around driveways, parking pads and garden beds
For tall walls, walls holding up a driveway or structure, and tight lots, engineered block or poured concrete is often the better fit. Many projects combine the two: an engineered wall where the load is, boulders where the look matters.
How are boulder walls built?
The builder excavates to firm ground, sets a base of compacted gravel or places the bottom row of the largest stones partly below grade, and stacks each course so stones lean into the slope with solid contact points. Drainage stone goes behind the rocks, and on wetter sites a perforated pipe carries water out. Gaps are chinked with smaller stone so soil doesn't wash through.
What are the risks of a poorly placed boulder wall?
- Stones set on loose fill or topsoil, which settle and tip
- Walls stacked too vertical, with no lean into the hill
- Round rocks with little contact between them
- Soil washing out through the gaps after rain
What affects the cost of a boulder wall?
- Stone size and source. Larger stones cost more to buy, haul and place.
- Equipment access. Boulder work needs an excavator or loader on site.
- Height and length. Taller walls use bigger stones and more base.
- Drainage. Wet slopes need drain rock and sometimes pipe.
- Lakefront rules. Work near the shoreline can require county or state approval.
Prices come from the builder after they've seen the site. We don't quote prices ourselves, and a phone estimate is only a starting point for a wall.
Where we connect you with help
Common questions
Do boulder walls need drainage?
Yes. Stone walls drain better than solid walls, but drainage stone behind the rocks, and sometimes a pipe, keeps water pressure from building up.
Can boulders be used along Lake Coeur d'Alene?
Sometimes, but shoreline work is regulated. Kootenai County limits work within 25 feet of the high water mark, and work below the high water mark generally needs an Idaho Department of Lands encroachment permit.
Related services
- Retaining wall installation
- Retaining wall repair & replacement
- Wall drainage & French drains
- Terraces, steps & tiered walls
More background: Kootenai County retaining wall guide.
Wall leaning, bulging or cracking?
A moving wall can fail suddenly. Keep people and vehicles clear and call to get it looked at.