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Know What Home Inspectors Look For - and how the find it!
Tips from a Certified Master Inspector to help you avoid surprises.
$12k–$20k Surprise? How to ID Poly-B Fast
The inspection I did last week on a “everything’s-great” (according to the seller) bungalow had one tiny problem: the water lines weren’t copper, weren’t PEX… they were gray.
Ten seconds later we had our answer—polybutylene (Poly-B). The buyers were thrilled we caught it early. The sellers? Still thankful—because we gave them a clear, calm plan that kept closing day on track.
On a 1989 bungalow, the house looked pristine. Under one bathroom sink, though, the supply lines were gray with copper crimp rings. One quick close-up showed PB2110 printed right on the tube. A second wide shot captured multiple gray lines branching above the mechanical room ceiling.
The agent forwarded our two photos to a plumber the same afternoon and got a ballpark the next morning. Instead of a last-minute scramble, the parties negotiated a credit and kept the possession date. No drama, no drift.
The Problem
Poly-B was widely installed in the late 1970s through the mid-1990s. Over time, it can become brittle at fittings and under high pressure or heat, leading to leaks.
Full pipe replacement commonly run in the $10k–$20k range for a typical detached home (more for larger/complex layouts), and drywall/paint restoration can add to the bill.
Surprise = panic = delays. But when you know the visual “cheat codes,” you can spot it fast, document it cleanly, and shift everyone into solution mode—not crisis mode.
How this Gets flagged
Visual cheat codes for Poly-B (PB):
Color/feel: Usually gray or taupe flexible tubing (sometimes silver-gray).
Print on pipe: Look for “PB” markings—often PB2110—printed along the tubing.
Era clues: Homes built/renovated ~1978–1995 are prime candidates.
Fittings: Barbed insert fittings with metal crimp rings (often copper). Older white/black plastic (acetal) fittings are a red flag.
Where to peek first: Under kitchen/bath sinks, mechanical rooms near the water heater, basement ceilings, behind furnace rooms, laundry valves, and at manifolds.
Not Poly-B (common mix-ups):
PEX is typically red/blue/white, clearly printed “PEX” (ASTM F876/F877).
Copper is, well… copper.
Black exterior service pipe is often polyethylene (different material).
The Fix
The fix is to replace it.
Why It Matters
No surprises = fewer dead deals. Early, clean documentation gives room to negotiate.
Insurance & disclosure peace of mind. Some insurers won’t insure Poly-B; having a plan prevents delays.
Real costs, real choices. For many North American markets, full re-pipes often fall ~$10k–$20k for typical homes; large or complex layouts can exceed that—especially when drywall and paint restoration are included. Clear numbers reduce fear.
Identifying Polybutylene
🛠️ Pro Tip
Inspector Pro Tip: How to ID “PB2110” Fast
Go where the print lives. You’re most likely to see markings on straight, accessible runs: under-sink supply risers, laundry boxes, or the mechanical room near manifolds.
What you’re hunting for: the pipe will be gray/taupe and the ink will show PB (often PB2110). You may also see codes like ASTM D3309 or CSA B137.8—both are Poly-B tells.
Don’t get fooled by gray PEX. PEX will literally say PEX and usually includes ASTM F876/F877. If the word PEX isn’t printed anywhere but PB/PB2110 is, you’ve found Poly-B.
Fittings are clues. Expect barbed insert fittings with copper crimp rings; older installs may have white/black acetal (plastic) fittings or QEST-branded parts—classic PB era hardware.
Lighting + angle = legible text. Use your phone flashlight at a low angle and rotate the pipe—the stamp repeats every 2–3 feet and is often on the “back” of the run. Wipe dust/paint first.
Quick doc method: Take a macro photo capturing both the PB2110 print and a fitting (ID shot), then a context photo of the area (extent shot). Label in-frame (“Powder Room – North Wall”) to make quotes easy.
Era check: Builds/renos from roughly late ’70s to mid-’90s are prime suspects (often later in parts of Canada). If the age fits and the pipe is gray, assume PB until the print proves otherwise.
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🔎 Coming Next Week…
Before It Burns, Catch This
One era. One material. One avoidable disaster. Aluminum branch wiring—what every buyer and agent should fear (and flag).
Ron Henderson, CMI
Certified Master Inspector
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Disclaimer: Some details in these stories have been modified to protect the privacy of individuals involved. While the events are based on real experiences, names, locations, and certain specifics may have been altered.
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