Seat walls and low retaining walls
Walls give a patio edges, extra seating and level ground on lots that slope toward the street or the back fence.
Many Tri-Cities neighborhoods sit on rolling ground, especially in south Kennewick toward the Horse Heaven Hills, around Badger Mountain in Richland, and on the hills of West Richland. A low retaining wall can flatten a sloped backyard enough for a patio, while a freestanding seat wall gives you built-in seating around a fire pit or along the patio edge.
Which wall does what?
| Wall | What it does | Things to know |
|---|---|---|
| Seat wall | Freestanding seating around a patio or fire pit | Usually 18 to 20 inches tall with a cap |
| Raised planter | Holds soil for beds and drip-irrigated plants | Needs drainage so water doesn't stain the face |
| Low retaining wall | Holds back soil to level a yard | Needs a base, gravel backfill and a drain |
| Taller retaining wall | Larger grade changes | May need geogrid, an engineer's design and a permit |
How are block walls built?
- A trench with a compacted gravel leveling pad, with the first course partly buried
- Courses set back slightly as the wall rises, per the block maker's guidance
- Clean gravel behind retaining walls, with a perforated drain at the base
- Caps glued down so they don't slide off
Why drainage still matters in a dry climate
The Tri-Cities gets little rain, but sprinklers, drip lines and the occasional heavy storm soak the soil behind walls all summer. Saturated soil pushes harder, and fine silty soils can wash out through gaps. Gravel backfill and a drain keep a wall straight. Keep sprinkler heads aimed away from the wall face to avoid hard-water staining.
When do I need an engineer or permit?
Taller walls, walls holding up a driveway or structure, and walls near property lines may need a permit and an engineered design. Check with your city's building department or ask the contractor to.
The contractor prices the job after seeing the site, measuring the area and talking through the pattern and materials you want. We don't quote prices, and a number given over the phone is only a rough starting point.
Where we connect you with help
Common questions
How tall can a seat wall be?
Seat walls are usually built about 18 to 20 inches tall so they're comfortable to sit on. A wall holding back soil is a retaining wall and is designed differently.
Can a wall be built to match my pavers?
Usually. Many paver makers sell wall block and caps in matching colors. Ask the contractor for samples.
Related services
More background: Tri-Cities paver patio guide.
Ready for a patio you'll actually use?
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