Retaining Wall Risk Checklist
Before You Build Retaining Wall - Read This.
​Planning a Retaining Wall in the Okanagan?
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How to protect yourself before you build.
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A retaining wall is a structural system, not landscaping. When it is done right, it lasts decades. When corners get cut, failures can show up fast – often after the contractor is gone.
Use this checklist to compare quotes, spot shortcuts, and protect your property before excavation starts.
How to use this checklist
• Walk the site and note the tallest wall height, wall length, and what is above/below the wall.
• Identify water sources: roof runoff, driveway runoff, irrigation, springs, and natural drainage paths.
• If the wall is tall, supports loads, sits near a structure, or has questionable soil/water conditions, involve a qualified engineer early.
• Take progress photos during construction (base, drain, reinforcement, backfill). Photos protect you later.
1) Define the wall’s job
• Measure total wall height at the tallest point (grade-to-grade). Height drives the design.
• Confirm what the wall supports: yard, driveway, parking, building, patio, pool, hot tub, septic, etc.
• Identify slopes above/below the wall that increase load or limit reinforcement space.
• Confirm property lines, setbacks, easements, and boundaries.
• Ask: “If this wall moves 2 inches, what breaks?” (driveway cracks, pool plumbing, foundation issues).
Reality: Many failures happen because a structural wall was treated like a decorative feature.
2) Site conditions and risk factors
• Soil type matters: clay, silt, sand, rock, fill, organics.
• Signs of “bad ground”: soft subgrade, pumping mud, buried debris, old fill.
• Water conditions: seepage lines, springs, wet zones, seasonal saturation.
• Tight access increases risk because shortcuts become tempting.
• Previous failures often repeat unless the underlying cause is corrected.
Red flag: “We build the same wall everywhere.”
3) Drainage behind the wall (the #1 failure point)
• Perforated drain pipe installed at the base of the wall in clean drain rock.
• A real outlet (daylight) or approved discharge path is required.
• Free-draining rock behind the wall (not native soil).
• Separation fabric/geotextile used appropriately to prevent fines migration and clogging.
• Drain outlets stay accessible and are not buried by landscaping.
• Ask: “Where does the drain exit?” and “Show me the outlet location on the plan.”
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Red flag: “It drains into the rock” with no outlet plan.
4) Surface water control
• Downspouts must discharge away from the retained zone.
• Driveway runoff must be directed away with positive grading or drainage control.
• Prevent ponding at the top of the wall; standing water becomes pressure.
• Irrigation must not saturate the retained zone or drainage zone.
• Planter beds and mulch must not block drain outlets.
Reality: Even perfect wall drainage fails if surface water is dumped behind the wall.
5) Engineering – when it is required
• Engineering is often required when walls are taller, support loads, sit near structures, or have limited reinforcement space.
• Surcharges that commonly trigger engineering: driveway/parking, building/foundation, pool, hot tub, septic, heavy landscape features.
• Steep slopes, poor soils, wet zones, tiered walls, and boundary walls increase risk and often require design.
• Expect a stamped design showing wall type, embedment, drainage, reinforcement, and elevations.
Red flag: “Engineering is a scam” or “we never need it.”
6) Permits, inspections, and municipal requirements
• Confirm whether your municipality requires permits at certain heights or conditions.
• If engineered, confirm inspections or verification requirements and who coordinates them.
• Ensure the crew builds from approved plans on site (no “field improvising” on structural items).
Reality: Rules vary. Homeowners get burned when nobody checks.
7) Wall system selection
• Select a system that matches the job: gravity wall, reinforced SRW (geogrid), large-format block, cast-in-place, rock, etc.
• Confirm the system is appropriate for structural retaining (not just landscaping).
• Confirm manufacturer limits and required details (base specs, max heights, reinforcement, drainage).
• Confirm durability considerations: freeze/thaw exposure, water contact, salt exposure, traffic.
Red flag: System chosen because it is cheapest or easiest – not because it fits the site.
8) Base preparation
• Excavate to competent subgrade (not just scraping the surface).
• Remove organics and unsuitable material.
• Install proper crushed aggregate base (correct type), compacted in controlled lifts.
• Base width and thickness match wall height and system/engineering requirements.
• First course embedment is correct for design, exposure, and frost conditions.
Red flag: Blocks set on dirt/clay or “we’ll just pack it down.”
9) Backfill and compaction
• Backfill in controlled lifts; compact each lift properly with the right equipment.
• Use correct materials behind the wall (free-draining rock + structural backfill as required).
• Moisture control matters: too dry or too wet will not compact properly.
• Prevent native fines from contaminating the drainage zone.
• Do not overload or push heavy equipment too close during early stages unless allowed by the system.
Reality: Most bulging walls are compaction failures.
10) Reinforcement (geogrid)
• If reinforcement is required, it is not negotiable.
• Grid installed at correct elevations and correct lengths (not cut short).
• Grid installed flat, tensioned, and properly connected to the wall system.
• Proper overlap and layout; sloppy seams reduce performance.
• Correct backfill material in the grid zone and consistent compaction between layers.
Red flag: Contractor suggests reducing grid “to save money.”
11) Wall geometry, batter, and alignment
• Correct batter/lean as required by the system or design.
• Courses fully seated; no debris between blocks.
• Alignment maintained consistently (string line/laser).
• Corners and curves built with proper units and lock-in methods.
• Caps seated and adhered properly per spec and site exposure.
Red flag: Wavy face, uneven joints, caps not seating, obvious step-outs.
12) Terminations, returns, step-downs, and transitions
• Most failures begin at ends and transitions – ensure there is a plan.
• Step-downs handled properly; avoid weak stair-steps without structure.
• Ends “die in” correctly or return into the slope as designed.
• Corners properly tied in; tie-ins to stairs/patios/driveways done with a clear detail.
Reality: A wall can be built fine in the middle and still fail at the ends.
13) Site access, staging, and execution plan
• Confirm staging areas for rock, blocks, excavated material, and disposal bins.
• Confirm property protection (driveway, structures, landscaping) and erosion control.
• Tight access plan: how materials and compaction will be done where machines cannot reach.
• Confirm who supervises daily and who your point of contact is on site.
Red flag: Fast quote with no plan for staging/access/logistics.
14) Utilities and unknowns
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• Utility locates planned before digging; confirm private lines (irrigation, lighting, drains, internet).
• Discuss rock, buried debris, and wet zones as realistic unknowns.
• Clear change-order process: written approval before extra work proceeds.
Red flag: “There won’t be any surprises.”
15) Scope, warranty, and change orders (contract clarity)
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• Quote must state wall type/materials, length, height definition, and exclusions.
• Drainage must be clearly described, including outlet location.
• Reinforcement/engineering must be included when required.
• Excavation, disposal, access assumptions, and restoration expectations must be clear.
• Warranty terms must be written, including what is excluded (movement from new loads/water changes, etc.).
• Change orders must be written and approved before proceeding.
Red flag: One-line quote: “Build retaining wall.”
16) Post-completion checks and early warning signs
• Keep drain outlets visible and clear. If water stops draining during wet seasons, investigate.
• Watch for bulging, leaning, joint separation, cap movement.
• Watch for settlement behind the wall at the top; address early.
• Avoid heavy loads near the top unless designed for it (hot tubs, vehicles, stockpiles).
• Keep photos of base, drainage, reinforcement, and backfill layers for your records.
Reality: Most failures give warning signs – people just ignore them.
FINAL THOUGHT
A retaining wall is a structural system, not landscaping.
When designed and built properly, it should last decades.
When corners are cut, failures can happen in months or a few years.
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ABOUT CASTLE RETAINING WALLS
Castle Retaining Walls specializes in engineered and large-scale retaining wall systems throughout the Okanagan.
Our work focuses on drainage, structural performance, and long term durability
- not cosmetic landscaping walls.
BEFORE
AFTER
Final Step Before You Build
If you're planning a retaining wall - or already have a quote - a professional review now can prevent costly failures later.
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We offer free retaining wall site reviews throughout the Okanagan.
​​​​​Thank You!
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If you’ve made it this far, you’re already ahead of most people.
This checklist highlights the most common mistakes we see causing retaining wall failures — often long before homeowners realize there’s a problem.
As you review it, pay close attention to:
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Drainage and water movement
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Wall height and soil conditions
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Slopes, driveways, or structures above the wall
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Whether engineering may be required
If even one item raises a question, that’s usually a sign to slow down and get clarity before moving forward.
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Want a Professional Set of Eyes on Your Site?
Castle Retaining Walls offers Free, No-Obligation Site Assessments for qualified projects.
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We’ll walk your site, review drainage and risk factors, discuss wall system options, and help you determine the right approach before you commit to construction.
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There’s no pressure and no obligation — just clear, professional input so you can make an informed decision.
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Call us directly at
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