Insurance Claims Sourcing: Forensic Engineers for Structural-Failure Denials

On a commercial property loss expert engagement after a major wind or rain event, the carrier almost never disputes that cracking, racking, or envelope separation is present. It disputes what caused it. The policy pays for some perils and excludes others, so the entire dollar value of the claim collapses onto a single engineering question: did the covered peril produce this specific structural condition, or did a pre-existing, gradual, or excluded mechanism.

The mechanism that makes this decisive is the way property forms allocate concurrent causes. Where a loss has both a covered cause (wind uplift, wind-driven rain through a breached envelope) and an excluded cause (long-term settlement, expansive soil movement, deferred maintenance, flood), the outcome depends on the policy's concurrent-causation language. Many commercial forms carry an anti-concurrent-causation clause that bars recovery if an excluded cause contributes to the loss in any sequence. Enforceability of that language varies by state: most jurisdictions enforce it as written, while a minority, including California, limit or override it through the efficient-proximate-cause doctrine, so confirm the governing state's rule before treating the clause as determinative. Under that language, the adjuster does not need to prove the exclusion caused the whole failure. They need a competing engineer to establish that an excluded mechanism contributed at all.

That is why sourcing is not a commodity task. You are not buying a report. You are buying a causation opinion that must isolate the failure mechanism, tie it to a covered peril to the exclusion of the excluded ones, and hold up when a defense engineer and a Daubert challenge attack the same physical evidence. Retain for the fight over mechanism, not for the description of damage.

A professional engineer license is necessary and not sufficient. Structural-failure claims split across at least three distinct competencies, and the wrong specialty produces an opinion that opposing counsel will disqualify on scope before it reaches the merits.

• Structural (SE or structural-discipline PE): load-path integrity, framing, connections, lateral systems, wind uplift and racking. Owns the question of whether the superstructure responded to a covered wind or pressure event.
• Geotechnical PE: soil behavior, bearing capacity, differential settlement, expansive and collapsible soils, hydrostatic uplift. Owns the question of whether the foundation moved because of the ground, which is frequently the excluded, earth-movement side of the dispute.
• Building-envelope or building-science specialist: water-intrusion pathways, cladding, fenestration, flashing, and the distinction between wind-driven rain through a storm-created breach (often covered) and long-term seepage or condensation (often excluded).

A foundation or building-envelope compromise after a hurricane routinely spans all three. The sourcing error to avoid is retaining a single structural PE to opine on soil mechanics, or an envelope consultant to opine on framing capacity. Where the failure crosses disciplines, retain a lead with a documented team, and confirm each opinion is authored and signed by the license that actually covers it. An opinion offered outside the signer's discipline is the cleanest disqualification a defense expert gets.

A defensible causation opinion reconstructs the load path and demonstrates why the observed damage pattern is consistent with the claimed peril and inconsistent with the alternatives. This is the mechanism attorneys should confirm the engineer will actually execute, because it is the part a competent adversary tests hardest.

• Wind and pressure demand: the engineer should establish the actual loading the structure experienced, referencing recognized load standards such as ASCE 7, event wind-speed data, exposure category, and building geometry, then compare demand against as-built capacity. A causation claim that never quantifies demand is an assertion, not an analysis.
• Damage-pattern signature: different mechanisms leave different fingerprints. Wind uplift and racking, hydrostatic foundation movement, expansive-soil heave, and differential settlement each produce characteristic crack orientation, displacement direction, and distribution. The report must explain why the observed signature matches the covered peril and rule out the excluded ones with evidence, not conclusion.
• Modeling proportional to the stakes: for high-value or contested losses, finite element analysis (FEA) can quantify stress and displacement under the event loads. FEA strengthens an opinion only when inputs, boundary conditions, and assumptions are documented and reproducible. An unvalidated model with hidden assumptions is a Daubert liability, not an asset.
• Alternative-cause elimination: the single most attacked weakness in causation testimony is failure to address obvious excluded causes. The engineer must affirmatively evaluate and, where the evidence supports it, exclude settlement, prior distress, maintenance, and construction defect. Silence on alternatives reads as bias.

In federal court and the many states that track it, expert engineering testimony is screened under Federal Rule of Evidence 702 and the Daubert v. Merrell Dow line, extended to non-scientific technical experts by Kumho Tire Co. v. Carmichael and reinforced by General Electric Co. v. Joiner. Frye-standard jurisdictions apply a general-acceptance test instead. You cannot guarantee admissibility, and no engineer can. You can vet for the factors a court weighs so the opinion is not stripped before trial.

• Testable, reproducible methodology: can another qualified engineer follow the stated method and reach the same result from the same data. Proprietary or unstated method is a gating risk.
• Known methods and standards: reliance on recognized load standards and published test protocols rather than ad hoc technique.
• Analytical gap: Joiner lets a court exclude opinion where too great a gap separates the data from the conclusion. Confirm every conclusion traces to a documented observation or calculation.
• Prior challenge history: ask directly whether the expert has been the subject of a Daubert or Frye motion, and the outcome. A prior exclusion in a similar matter is discoverable and material to your sourcing decision.

Treat the 2023 amendments to Rule 702 as raising the burden the proponent must meet on reliability. Source engineers who write toward that burden, and confirm their reports state the basis for each opinion rather than leaving the court to infer it.

Causation opinions rest on perishable field evidence: crack-monitor readings, moisture-meter data, elevation surveys, borehole logs, water-test results, and hundreds of photographs. If the provenance of that data is impeachable, the opinion built on it is impeachable. Vet the engineer's evidence-handling discipline as rigorously as the analysis.

• Standardized in-field testing: where water intrusion is at issue, recognized protocols such as ASTM E2128 for evaluating wall water leakage, ASTM E1105 for field water penetration of installed windows and curtain walls, and ASTM C1601 for masonry wall water penetration give the data a defensible, repeatable basis. Ad hoc hose testing does not.
• Instrumentation and timestamps: confirm calibration records for meters and monitors, and that readings are dated and attributable. Differential settlement claims often require repeat elevation surveys over time, so the first survey's timing and method become load-bearing.
• Digital evidence integrity: for photographic and sensor evidence, hashing files with SHA-256 (MD5 is deprecated for integrity purposes) and preserving original metadata lets you prove images were not altered between capture and production. Confirm the firm has a written chain-of-custody procedure, not just a habit.
• Preservation and spoliation: destructive testing that removes cladding or opens assemblies can destroy the other side's evidence. Confirm the engineer documents conditions before any invasive work and coordinates notice, or you inherit a spoliation problem that outlives the coverage question.

Reduce the sourcing decision to an auditable scorecard so two reviewers reach the same conclusion from the same file. Score each candidate across these axes and retain the record.

1. License and jurisdiction: PE (and SE where the state or scope requires it) in active good standing in the state of loss. Verify against the state board, not the resume.
2. Discipline fit: the signing license matches the failure mode. Multi-discipline losses show a named team with per-opinion signers.
3. Domain track record: documented experience with the specific peril and structure type (wind, foundation, envelope; commercial vs. residential).
4. Methodology posture: writes to standards and reproducible method; quantifies demand; addresses and eliminates alternative causes.
5. Testimony and challenge history: deposition and trial experience, and disclosed Daubert/Frye outcomes.
6. Evidence discipline: written chain-of-custody, calibration records, standardized test protocols, digital-integrity practice.
7. Independence and conflicts: no undisclosed relationship with the carrier, insured, TPA, or a party in the construction chain.
8. Capacity and timeline: ability to inspect before conditions change or repairs proceed, and to meet disclosure deadlines.

The two disqualifiers that should stop a retention regardless of score: an opinion offered outside the signer's discipline, and a methodology the engineer cannot or will not make reproducible. Both are fatal at the admissibility stage, so catch them at sourcing.

The engagement letter is a claim-outcome document. Scope defined loosely produces an opinion that wanders outside the license or omits the alternative-cause analysis that decides the concurrent-causation fight.

• Define the question, not just the task: state the causation question in policy terms so the engineer's scope maps to the covered-versus-excluded peril distinction that will decide the claim.
• Independence language: the opinion follows the evidence regardless of which side retained the firm. This protects the expert on cross and protects you from a bias attack.
• Authorize the right testing: specify non-destructive investigation first, and require notice and documentation before any destructive testing to control the spoliation exposure.
• Privilege posture: decide up front whether the engineer is retained as a consulting expert (work protected) or a testifying expert (opinions and most materials discoverable). Draft accordingly, and do not blur the two.
• Deliverable standard: require that each conclusion state its factual and analytical basis, so the report is written to the reliability burden rather than retrofitted after a challenge.

None of this guarantees coverage or admissibility. It is procurement discipline that makes the resulting opinion defensible, which is the most a well-run sourcing process can deliver.