A retaining wall contractor can either save your property from erosion or cost you thousands in repairs if they cut corners. Before signing a contract, you need to verify their track record through references—people who've actually hired them and lived with the results. Here's how to do it systematically and spot red flags before money changes hands.
Why References Matter for Retaining Walls
Retaining walls involve structural calculations, proper drainage, compaction, and material selection that directly affect how long a wall lasts. A contractor might look licensed and insured on paper but still install inadequate drainage, skip backfill layers, or use substandard materials that fail within five years. References from past customers reveal whether the contractor delivers on those hidden details.
Getting a Reference List from the Contractor
Ask the contractor for at least three to five references—ideally five—of projects completed in the last three years. Request references that match your wall type: if you need a timber retaining wall, ask for timber projects; if you're doing a concrete block or poured concrete wall, get similar examples.
Don't accept vague promises like "I'll send you a list." Get it in writing before you meet, so you have time to contact people before your next conversation with the contractor. If they resist providing references or claim all their customers prefer anonymity, that's a warning sign.
What to Ask Past Customers
When you call a reference, go beyond "Were you happy?" Use these specific questions:
- Did the wall drain properly after heavy rain? Poor drainage is the #1 reason retaining walls fail. Ask if they've seen any bulging, cracking, or water pooling behind the wall.
- How much settlement or movement have you noticed? Some settling is normal in the first few months, but significant shifts later indicate poor compaction or design issues.
- Did the contractor stay on schedule and budget? Retaining walls typically run $25–$75 per linear foot depending on height and materials; ask if the estimate held.
- What's the condition of the wall now, years later? A three-year-old wall should show minimal wear if built correctly. Ask about moss, crumbling mortar, or structural cracks.
- Would you hire this contractor again? This simple question cuts through politeness and gets honest sentiment.
Visiting Past Projects In Person
If a reference is local, ask permission to drive by and look at the wall yourself. Bring a level, take photos, and check for:
- Vertical alignment: The wall should be plumb or intentionally battered (angled back) as designed. Walls leaning forward are installing poorly.
- Joint consistency: Mortar joints (if applicable) should be uniform and intact, not crumbling or unevenly filled.
- Drainage: Look for water staining, moss growth, or weeping holes functioning as intended.
- Cracks: Fine hairline cracks are normal; wider cracks (over ¼-inch) or horizontal cracks suggest structural problems.
Checking Credentials Alongside References
References alone aren't enough. Verify that the contractor holds:
- Current contractor's license (check your state or county licensing board)
- General liability insurance (minimum $1 million; ask for a certificate)
- Workers' compensation insurance if they employ staff
- Bonding for larger projects (typically $10,000–$100,000)
Call the insurance company directly to confirm coverage is active—don't rely on documents the contractor provides.
Using Reference Platforms
Platforms like Google Reviews, Yelp, and Angie's List show verified customer feedback, though they're less detailed than one-on-one calls. Look for patterns: one bad review is noise; three complaints about poor drainage or cracking are data. Read both positive and negative reviews for specifics—generic praise ("great guy") is less useful than detailed accounts ("fixed the drainage problem that was causing water damage").
You can also use services like Mercoly, which aggregate trusted retaining walls contractors in your area and compile verified customer experiences, making it easier to compare multiple contractors' references side by side.
Red Flags to Watch For
- No references available or only photos with no contact info
- References who only know the contractor personally (not as a client)
- Multiple references with the same phone number or email
- Vague or evasive answers about structural failures
- Prices significantly below market (usually means corners are being cut)
Frequently Asked Questions
Q: How long should a retaining wall last if built correctly? A properly constructed retaining wall should last 50+ years for concrete or stone, and 15–20 years for timber depending on wood type and climate. Ask references about maintenance they've needed to plan your budget.
Q: Should I hire the contractor with the most references, or the cheapest? Neither—hire the contractor whose references consistently describe durability, proper drainage, and on-time completion at a mid-to-high market rate. The cheapest estimate often means inadequate materials or labor shortcuts.
Q: Can I build a retaining wall myself to save money? Retaining walls over 4 feet typically require engineering and permits; building incorrectly risks property damage and liability. Unless you have structural or civil engineering experience, hire a licensed contractor.
Compare contractor references today on Mercoly to find verified, trusted retaining wall builders in your area.