Large commercial buildings: TIV, coinsurance, and the appraisal fight.

The commercial property forms

A large commercial building is not insured on a homeowners form at all. It runs on the ISO Commercial Property program, built around CP 00 10, the Building and Personal Property Coverage Form. On its own, CP 00 10 does not name a single covered peril; it has to have a Causes of Loss form attached to say what counts: CP 10 30 (Special, the broadest, open-perils), CP 10 20 (Broad), or CP 10 10 (Basic). Hurricane wind is a covered cause under all three. Business income rides on CP 00 30, and ordinance-or-law on CP 04 05.

The difference from a homeowners claim is structural. The commercial program layers coinsurance, valuation conditions, and a formal appraisal clause onto a loss that is already large enough for the carrier to litigate. Every one of those layers is a place the payment can come in below the loss, and the first of them is the number the whole policy is built on: Total Insured Value.

Total Insured Value (TIV)

Total Insured Value is the sum of everything at risk at the location: the building, the business personal property (contents, equipment, inventory), and the business income time-element value. It is the figure premiums are built on and, critically, the figure the coinsurance requirement is measured against. Understate the TIV, and the coinsurance penalty is set before a storm ever forms.

Understated TIV is rarely deliberate; it is usually stale. A building valued five years ago, insured to that number ever since, is underinsured the moment construction and material costs climb, and after 2020 they climbed hard. When the loss comes in and the adjuster rebuilds the replacement cost at current prices, the gap between the old insured value and the true value becomes the coinsurance shortfall. The fix is a current, defensible valuation; the failure to keep one is what the next section charts.

The coinsurance penalty

Coinsurance is the mechanism that turns underinsurance into a proportional cut on every claim. The clause requires you to insure the building to at least a stated percentage of its value, commonly 80%, 90%, or 100%. Insure it for less, and the carrier pays only the fraction you did insure. The formula:

THE COINSURANCE FORMULA (STANDARD COMMERCIAL PROPERTY WORDING)

RECOVERY = ( LIMIT CARRIED ÷ LIMIT REQUIRED ) × LOSS − DEDUCTIBLE
where LIMIT REQUIRED = COINSURANCE % × PROPERTY VALUE

One nuance worth confirming in your own policy: whether the deductible is subtracted before or after the coinsurance factor is applied is set by the Loss Payment condition, and it changes the final number. But the headline does not change: a building insured to 75% of its required limit collects 75 cents on the dollar for every covered loss, storm after storm, until the valuation is corrected.

Roof-system claims

On a large building the roof is the largest single component of the claim, and the most technical. Commercial roofs are membrane systems (single-ply TPO or EPDM, modified bitumen, built-up gravel) attached to the deck by mechanical fasteners, adhesive, or ballast. Hurricane wind does not just tear them the way it strips shingles; it lifts the membrane by uplift pressure, breaks the seams, and admits water across the entire deck. The damage is often invisible from the ground and only shows in an uplift test or an infrared moisture survey.

That creates the recurring commercial roof fight: the carrier scopes a spot repair to a membrane that has actually released across the field, or attributes seam separation and ponding to age and "deferred maintenance" rather than storm uplift. The counter is engineering: a roofing consultant’s uplift and moisture testing, wind-field data for the address, and the manufacturer’s attachment specification, establishing that a system-wide failure needs a system-wide replacement, not a patch. And a full replacement is exactly what pulls the next coverage into play.

Ordinance & law coverage

A base property policy pays to rebuild what you had, not to rebuild it to today’s code. On a building that predates the current code cycle, that gap is enormous, and ordinance-or-law coverage (ISO form CP 04 05) is what fills it. It comes in three parts, and large hurricane claims trigger all three:

• Coverage A, undamaged portion. Pays for the loss in value of the undamaged part of the building that an ordinance requires you to demolish (this shares the building limit; it is not a separate pot).
• Coverage B, demolition cost. Pays to demolish and clear away the undamaged portion the ordinance condemns.
• Coverage C, increased cost of construction. Pays the extra cost of rebuilding both the damaged and undamaged portions to meet the current code: the impact windows, the tie-downs, the strengthened roof deck the old building never had.

Florida’s roofing rule is the textbook trigger. Under Fla. Stat. § 553.844 and the Florida Building Code, a repair or replacement of 25% or more of a roof historically forced the entire roof up to current code, a Coverage C cost that could dwarf the storm damage itself. SB 4-D (2022) softened it: § 553.844(5) now provides that if the existing roof was built or replaced under the 2007 Florida Building Code or later, a 25%-or-more repair requires only the affected portion to meet current code. On older buildings the full 25% rule (and the ordinance-or-law exposure behind it) still bites, and Coverage C’s percentage limit is often the number that runs out first on a large loss.

Appraisal at scale

Most large commercial hurricane disputes never see a jury on the dollar amount; they go to appraisal. The appraisal clause in the Commercial Property Conditions (ISO form CP 00 90) lets either party, when the amount of loss is disputed, demand a private valuation. Each side names a competent and impartial appraiser; the two appraisers select an umpire, and if they cannot agree, a court appoints one. Each appraiser states the amount, and the agreement of any two of the three is binding as to the amount of loss. Each party pays its own appraiser and splits the umpire’s cost.

ISO CP 00 90 · APPRAISAL CONDITION (TYPICAL WORDING)

"If we and you disagree on the value of the property or the amount of loss, either may make written demand for an appraisal of the loss… If the appraisers do not agree, they will submit their differences to the umpire. A decision agreed to by any two will be binding."

The line that decides how appraisal is used: it resolves value, not coverage. If the carrier disputes the amount of a covered loss, appraisal is fast, binding, and often favorable. But if the carrier denies coverage outright, pointing at an exclusion, a coinsurance dispute over the required limit, or a claim that the damage predates the storm, the appraisal panel has no power to decide it, and that question stays with the courts or the settlement table. A well-run commercial claim keeps the lanes separate and does not let a coverage denial get laundered into an amount dispute. Florida’s notice deadlines (§ 627.70132) run the whole time, so the appraisal demand cannot become a reason to miss the filing window.

Florida vs. South Carolina

ISO form summaries and statutes are summarized as of July 2026 and drafted for education, not verified by counsel, and policy editions and building-code cycles differ. Confirm the coinsurance percentage, the ordinance-or-law limits, and the appraisal wording on your own policy before relying on it.

Large commercial building claims: the questions owners ask

Independent informational resource, not legal advice. ISO form language, statutes, and the coinsurance math are drafted for education and have not been verified by counsel; exact wording is edition- and policy-specific. Consult an attorney about your specific claim.