Site Grading & Drainage
Every hardscape failure starts
with a drainage decision that wasn't made.
The patio that heaved after the first winter. The retaining wall that pushed out after three years. The driveway that washed and rutted every spring. These aren't structural failures — they're drainage failures. Water that had nowhere to go found somewhere: through the base, behind the wall, under the slab.
LP designs drainage into every hardscape project before a single material is ordered. Surface slopes, French drain locations, and outlet routing are part of the design — not an afterthought. Post Falls, CDA, and Rathdrum soils don't forgive drainage oversights. We've been engineering around that since 2005.
Drainage engineers who also build
the surfaces they're protecting.
Drainage Designed from the Start
LP includes drainage design in every hardscape estimate — not as an add-on after the patio is built. Surface slope, French drain placement, and outlet routing are designed before any material is laid. This is the difference between a hardscape that looks good for decades and one that develops problems after the first heavy rain.
Excavation and Hardscape as One Scope
Because LP owns excavation equipment and hardscape crews, drainage grading and hardscape installation happen under one contract. No coordination between a separate grading contractor and a hardscape company. One project manager, one estimate, one accountable team.
North Idaho Soil Knowledge
Post Falls, CDA, and Rathdrum soils vary from sandy loam to dense clay — and the drainage solution differs significantly between them. LP's crews know the local soil conditions and specify drainage solutions appropriate for each site. A French drain that works perfectly in sandy soil is undersized for clay.
Wall Failure Prevention
Drainage behind retaining walls is the single most important factor in whether a wall lasts 5 years or 30 years in North Idaho. Hydrostatic pressure from trapped water is the primary cause of retaining wall failure. LP's integrated wall drainage is not optional — it is engineered and installed on every structural wall we build.
Every drainage type for every
hardscape application.
Patio Surface Drainage
Every LP patio is designed with positive drainage — a minimum 1–2% slope away from structures, and surface features (channels, slot drains, or natural grade breaks) that route water off the surface before it pools. Pooling water on a patio surface is a drainage design failure, not a maintenance issue.
French Drains
Perforated pipe in a washed gravel trench, wrapped in filter fabric — captures subsurface water migrating toward patios, walls, and foundations. LP installs French drains at the base of retaining walls, along patio edges, and at grade break points where water collects. Outlet routing to daylight or a dry well is engineered as part of every French drain design.
Earthen & Paved Swales
Graded earthen channels redirect surface water away from hardscape areas and toward designed outlets. Paved or rock-lined swales are used where flow velocity would erode an earthen channel. LP's grading work is coordinated with adjacent hardscape surfaces so water moves in the right direction at every grade break.
Slope & Grade Management
Regrading around existing patios, walls, and structures to correct drainage patterns that have shifted over time. LP's excavation capability allows us to regrade slopes adjacent to hardscape areas, redirect water away from structures, and add compacted fill where settling has created low spots that hold water.
Retaining Wall Drainage Systems
Drainage engineering specifically for retaining wall base and backfill: perforated drain pipe at the wall footing, washed drainage aggregate in the backfill zone, and geotextile fabric separation between the drainage rock and native soil. This is not optional on LP walls — it's standard installation practice for every structural wall we build.
Channel Drains & Area Inlets
Cast-in-place or prefabricated channel drains at garage entries, patio low points, and driveway aprons capture surface water and route it to a designated outlet. Area inlets (catch basins) collect concentrated surface runoff. Both are coordinated with the surface grade design so water reaches the drain rather than pooling beside it.
Drainage work across Kootenai County.
Trusted by North Idaho homeowners
for drainage that works.
"LP installed a French drain along our retaining wall and regraded the swale. The wall had been moving for years due to water pressure. They've been rock solid since. Their drainage expertise is exactly what you need in North Idaho's wet climate."- Robert S., Hayden
"Our paver patio was pooling water after every rain. LP assessed the drainage and installed channel drains with proper outlet routing. No more standing water. They understand how water moves in our clay soils."- Lisa T., Coeur d'Alene
"LP retrofitted drainage around our existing concrete patio. They dug up sections, installed French drains, and restored everything perfectly. The patio no longer heaves in winter. Family-owned business with real expertise."- David K., Post Falls
"The drainage system LP designed for our boulder wall has kept it stable through multiple wet winters. They know the local soil conditions and engineered the right solution. Worth every penny for peace of mind."- Karen M., Spirit Lake
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