Retaining Wall Risk Checklist
Before You Build Retaining Wall - Read This.
Planning a Retaining Wall in the Okanagan?
How to protect yourself before you build.
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.”
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
• 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)
• 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.
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.
We offer free retaining wall site reviews throughout the Okanagan.
Thank You!
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.
Want a Professional Set of Eyes on Your Site?
Castle Retaining Walls offers Free, No-Obligation Site Assessments for qualified projects.
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.
There’s no pressure and no obligation — just clear, professional input so you can make an informed decision.
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