How to Tell If Your Dock Pilings Need Repair or Replacement

Every dock owner faces this question eventually: are these pilings worth saving, or does it make more sense to pull them and start fresh? The answer depends on a single factor — structural integrity — but getting to that answer requires knowing what to look for, where to look, and what the damage actually means.

Making the right call early saves money. Making the wrong call — assuming pilings are fine when they are not — creates safety hazards. Here is how to approach the decision.

What Piling Damage Actually Looks Like

The most damaging myth about dock pilings is that you can judge them by looking at the surface. You cannot. The two primary threats to Gulf Coast wood pilings — Teredo shipworms and Limnoria crustaceans — do most of their damage below the waterline and from the inside out.

Teredo worms enter a piling through a tiny pinhole in the surface, then excavate long tunnels through the interior, following the grain of the wood. A piling can be 70% hollow and show nothing but a handful of small holes on the exterior. Limnoria work differently — they erode the surface progressively, creating the characteristic "hourglass" shape visible just below the waterline where tidal action concentrates the most biological activity.

Above-Waterline Clues

Above the waterline, look for: longitudinal splitting or deep cracking, soft spots when probed with an ice pick or spike, visible erosion or wood fiber separation, and hardware that has pulled loose from the wood. These are signs of structural weakening, though they don't tell you what's happening below.

Below-Waterline Assessment

Below the waterline, you need either an underwater inspection (dive or camera) or core sampling to understand actual condition. The splash zone — the area that alternates between wet and dry with tidal action — is often the most aggressively damaged, because it combines biological attack from borers with physical weathering and the wet-dry cycle that accelerates wood decay.

When Repair Is the Right Answer

A piling is a good candidate for repair — through wrapping, encapsulation, or both — when the following conditions are true:

• The piling retains structural integrity at its base. The base (buried in sediment) must be sound. If the piling is compromised at its embedment point, replacement is usually required because no above-grade treatment reaches the base.
• The cross-sectional loss is less than about 40–50%. Pilings retain substantial load-bearing capacity with significant interior damage, but beyond a certain threshold, the risk of failure under load becomes unacceptable.
• The damage is from biological attack rather than physical failure. Marine borer damage, surface erosion, and early-stage rot are amenable to restoration. Shattered pilings, failed piling-deck connections, or pilings that have shifted out of vertical alignment are different problems.
• There is no active settlement or movement in the dock. If the dock is visibly settling or the deck is distorting, the pilings may already be compromised to a degree that requires replacement.

When Replacement Is Necessary

Replacement becomes the right answer when a piling is structurally failed at the base, has lost more than 50% of its cross-section to damage, has physically shifted or leaned beyond correctable limits, or is a species not amenable to encapsulation (some treated wood types have poor adhesion characteristics). A reputable inspector will tell you when replacement is the right answer — even when repair is more profitable for the contractor.

The Cost Case for Repairing Early

The economics of piling protection versus replacement are straightforward. Protecting a sound piling — even one with early-stage borer damage — is significantly less expensive than letting that damage progress to the point where replacement is required. On the Gulf Coast, piling replacement costs typically run $1,500–$3,500 per piling including permits, materials, and labor. Protection with a quality wrap and encapsulation system typically runs 40–70% less than that figure — and extends piling life for decades rather than starting the clock over with a new unprotected piling.

The hidden cost of waiting is that every season of unprotected exposure accelerates the damage. A piling that could have been protected for $400–$800 in year three may require a $2,500 replacement by year eight. The inspection is free. The information you get from it is invaluable.

Getting a Professional Assessment

The only way to make a genuinely informed repair-versus-replace decision is a professional inspection by someone who has seen hundreds or thousands of pilings in Gulf Coast conditions. An experienced inspector can assess piling condition above and below the waterline, identify the type and extent of damage, and give you a clear, honest recommendation about which pilings are worth protecting and which need to be replaced.

Deep South Marine Restoration offers free on-site inspections throughout Louisiana, Mississippi, Alabama, Florida, and Texas. We give you the honest answer — whether that means protection, replacement, or a combination of both — before any work begins.