Insurance disputes involving interior water damage caused by rain entering from the exterior of the building often turn on a deceptively simple question: Did wind or other covered peril create an opening that allowed the rain to enter? A recent California appellate decision offers a hard lesson about what happens when that question is not nailed down early, clearly, and with admissible evidence. 1
The policy in this case contained the common rain limitation found in many commercial property forms. The limitation stated:
“We will not pay for loss of or damage to the interior of any building or structure, or to personal property in the building or structure, caused by rain, snow, sleet, ice, sand or dust, whether driven by wind or not, unless the building or structure first sustains damage by a Covered Cause of Loss to its roof or walls through which the rain, snow, sleet, ice, sand or dust enters.”
That single sentence became the fulcrum on which the entire case turned.
Railroad Business Park suffered sudden and extensive interior water damage during a series of violent storms. The owner, a licensed contractor, found multiple openings in the roofing membrane that had not existed before the storm. A longtime roofer patched the newly torn areas and told the insurance adjuster the damage was caused by wind. The adjuster agreed. Travelers initially paid a small amount, and no one suggested the roof had deteriorated or that coverage was in question. Travelers never issued a denial, never amended its claim notes, and never reversed its original coverage determination.
But in litigation, years later, Travelers retained a consultant who inspected the roof long after the fact and opined that the membrane had not been wind-damaged but had simply deteriorated with age. The district court accepted this as the only admissible expert testimony because the policyholder’s construction expert did not provide the methodological foundation required by the federal rules of evidence. Travelers then successfully argued in the trial court 2 that the owner and roofer could not give opinions about causation because they were lay witnesses, leaving no admissible evidence that a wind-created opening had occurred.
Once the case reached the appellate stage, the result followed the same logic. With only Travelers’ expert left standing, there was no evidence, at least no admissible evidence, that wind first damaged the roof. Without proof that wind created an opening, the rain limitation barred coverage for the interior damage as a matter of law. The court affirmed summary judgment not because the facts clearly favored Travelers, but because the evidentiary record failed to contain the type of admissible testimony needed to survive the rain limitation’s strict causation requirement.
There is a valuable lesson here for policyholders, public adjusters, and policyholder attorneys. When dealing with water intrusion claims involving this type of policy wording, it is essential to obtain clear, contemporaneous, and preferably written agreement from the insurance company that the building first sustained wind damage that allowed the rain to enter. If the insurer will not acknowledge that fact, then a qualified expert must be retained immediately. This should ideally be someone who can inspect the roof before repair or deterioration obscures the evidence. Some courts may not let lay witnesses fill that gap, and memories and photographs often cannot substitute for sworn, methodologically grounded expert testimony.
In many ways, this case reminds us that insurance is a promise conditioned on proof. Even when everyone at the time of loss seems to agree that wind tore the roof open, the only proof that matters later is the proof a court can admit. The safer course, every time, is to lock down agreements about coverage in writing and obtain causation evidence early.
For readers interested in this topic, I suggest further study found in Contractor Testimony About Wind Causing Damage Allowing Rain to Enter a Building Is Important, and Wind-Driven Rain Versus Wind-Created Opening in a Building and Potential Coverage Implications.
Thought For The Day
“An ounce of prevention is worth a pound of cure.”
Benjamin Franklin
1 Railroad Business Park v. Travelers Cas. Ins. Co. or America, No. 24-5384, 2025 WL 3295116 (9th Cir. Nov. 26, 2025). (See also, Appellants Opening Brief).
2 Railroad Business Park v. Travelers Cas. Ins. Co. or America, No.2:20-cv-02189 (E.D. Cal. Aug. 2, 2024).