Segmental Block Retaining Walls

Segmental block retaining walls (Allan Block, Versa-Lok) in Post Falls and Kootenai County typically run $25–$50 per square foot of wall face, depending on wall height, geogrid requirements, drainage complexity, and site access. A 40-linear-foot, 3-foot-tall garden wall often runs $3,000–$5,500. Walls over 4 feet requiring geogrid reinforcement and permits will be higher. LP provides written, itemized estimates after an on-site assessment — wall costs cannot be accurately quoted without seeing the site.

In most Kootenai County residential zones, retaining walls under 4 feet in height (measured from bottom of footing to top of wall) do not require a permit. Walls 4 feet or taller, walls supporting a surcharge (like a driveway or structure), and walls within 10 feet of a property line typically require a permit and engineered drawings. LP handles permit research, design coordination, and inspection scheduling as part of every permitted wall project.

The two primary causes of retaining wall failure in North Idaho are inadequate drainage and insufficient geogrid reinforcement. When water saturates the soil behind a wall and has nowhere to go, hydrostatic pressure builds against the wall face — eventually pushing it out. LP installs perforated drain pipe at the base of every structural wall, washed rock drainage aggregate behind the wall face, and geotextile fabric separation. On taller walls, geogrid reinforcement layers are tied back into compacted fill at engineered intervals. Walls built without these elements typically fail within 5–10 Idaho winters.

Both Allan Block and Versa-Lok are engineered segmental retaining wall systems designed for residential and light commercial applications. Allan Block uses a setback-dependent gravity design — the block face angles back slightly with each course, creating the wall's structural resistance. Versa-Lok uses a pinning system with metal or fiberglass pins through each unit, allowing for near-vertical wall faces. Allan Block is generally more available locally and has a softer visual texture. Versa-Lok is preferred for tighter footprint applications or walls where a more vertical face is desired. LP recommends based on site conditions, wall height, and aesthetic goals after an on-site assessment.

Yes — terracing with retaining walls is one of the highest-ROI improvements you can make on a sloped North Idaho lot. LP designs multi-tier systems that convert steep, unusable hillside into level outdoor living areas, usable lawn, garden beds, or patio space. The complete scope — site excavation, structural fill compaction, wall construction, drainage, and finish grading — is handled by one LP crew. Most sloped-lot terrace projects run $12,000–$45,000+ depending on the total area to be converted and number of tiers required.