Updated October 1, 2026.
On a standard ISO HO-3 homeowner policy, Coverage A insures the dwelling, Coverage B insures detached other structures, Coverage C insures personal property, and Coverage D insures loss of use (additional living expense). Each part has its own limit, peril basis, and valuation rules, so a single storm can produce four different coverage outcomes. Commercial property policies use the same letter labels differently—buildings under Coverage A and business personal property under Coverage B—so the letters are a map, not a universal definition.
Why policies split property into A, B, C, and D
Property insurance separates what was damaged, where it sits on the premises, and what financial loss followed. That split drives limits, deductibles, coinsurance, and proof requirements at claim time. The ISO HO-3 Special Form is the reference architecture for most U.S. homeowners policies; commercial risks typically use ISO CP 00 10 with related causes-of-loss and business income forms. For the full property insurance decision framework—limits, valuation, and exclusion gaps—see Property Insurance: The Complete Professional Guide (2026).
Reinsurance and alternative capital still shape what carriers can write at what price. Catastrophe bond issuance reached a record of roughly $18 billion in the first half of 2026 (Artemis), with property cat bonds alone above $17 billion. That capacity supports catastrophe-exposed property lines; it does not change the four-part structure on your dec page.
Coverage A: Dwelling (residential) and buildings (commercial)
Residential Coverage A
Coverage A is the limit for the main dwelling and attached structures—foundation, framing, roof, built-in appliances, and permanently installed equipment. Under HO-3, Coverage A is written on an open-perils basis: direct physical loss is covered unless the policy excludes or limits it. Flood, earth movement, and several water-related losses are excluded; those gaps need separate policies or endorsements, as covered in Property Insurance Exclusions: What Standard Policies Do Not Cover and How to Fill the Gaps.
The Coverage A limit must track current replacement cost, not market value or original purchase price. When the limit falls below the carrier’s coinsurance requirement (often 80% of value at time of loss), partial losses are reduced by a coinsurance penalty. Extended replacement cost or guaranteed replacement cost endorsements change that math but do not remove the need for a defensible limit at renewal.
Valuation on Coverage A
Whether the carrier pays actual cash value (ACV), replacement cost value (RCV), or an agreed amount is stated on the declarations page and in endorsements. ACV subtracts depreciation; RCV pays without depreciation but often holds back depreciation until repairs are documented. The payment difference on older roofs and mechanical systems is routinely tens of thousands of dollars on a single claim. See What Agreed Value Means in Insurance (vs ACV and RCV) for how each method behaves at settlement.
Commercial Coverage A
On ISO commercial property forms, Coverage A insures buildings, including completed additions, fixtures, and permanently installed machinery and equipment. Tenant improvements and betterments may belong to the tenant’s policy depending on the lease. Smaller commercial accounts sometimes bundle property and liability in a Business Owner’s Policy (BOP): Coverage Structure, Eligibility, and Limitations; larger schedules usually use standalone commercial property and business income forms.
Coverage B: Other structures (homeowners) and business personal property (commercial)
Homeowners Coverage B
Coverage B insures detached structures on the residence premises—garages, sheds, fences, guest houses, and similar items not attached to the dwelling. The default limit is commonly 10% of Coverage A unless you increase it on the declarations page. Coverage B is open perils on HO-3, matching Coverage A, but the limit is separate. A total loss to a detached shop can exhaust Coverage B while Coverage A remains intact for the house.
Commercial Coverage B
On commercial property policies, Coverage B is business personal property (BPP): furniture, inventory, machinery, tenant improvements you own, and property of others in your care when covered by contract. Causes of loss may be special (open perils) or named perils depending on the form purchased. BPP limits should reflect peak values, not average inventory on a quiet month.
Coverage C: Personal property
Coverage C insures personal property owned or used by household members, usually worldwide for property temporarily away from the residence. On HO-3, Coverage C is named perils only—typically the ISO sixteen-peril list—so the carrier must show the loss resulted from a listed cause. That asymmetry matters when the dwelling is covered under open perils but contents are not, especially for water and power-loss scenarios.
The default Coverage C limit is often 50% of Coverage A. Scheduled floaters are used for jewelry, fine art, collectibles, and business property kept at home; unscheduled sublimits apply to cash, securities, watercraft, and other classes listed in the policy. Inventory the home on replacement cost terms where the carrier offers an RCV endorsement for contents.
Coverage D: Loss of use and additional living expense
Coverage D pays necessary increases in living costs when a covered loss makes the residence uninhabitable, and may include fair rental value if you rent part of the home. The standard limit is often 20% of Coverage A on HO-3; some carriers offer higher percentages by endorsement. Coverage D responds only to loss caused by a peril insured under Coverage A (and sometimes other property coverages as the form defines)—not to flood or earthquake unless those perils are insured elsewhere.
Document ALE carefully: temporary housing, storage, restaurant meals above normal food spend, laundry, and pet boarding. Carriers compare receipts to pre-loss household patterns. NFIP flood policies do not include ALE; that gap is one reason high-value homes carry private flood coverage in addition to NFIP where available.
How the four parts interact at claim time
One event, multiple coverage parts: wind damages the roof (Coverage A), destroys a fence (Coverage B), soaks contents (Coverage C if the peril is covered), and forces relocation (Coverage D). Each part may carry the same property deductible or endorsements that apply only to certain coverages. Ordinance or law costs often attach to Coverage A but are excluded unless endorsed.
From first notice through proof of loss, how you allocate damage across A–D affects reserve setting and payment timing. The workflow is laid out in Property Claim Filing and Documentation: From First Notice of Loss to Settlement.
Frequently asked questions
What does Coverage A cover on a homeowner policy?
Coverage A covers the dwelling and attached structures for direct physical loss from covered perils. On HO-3, that is open perils on the structure unless the policy excludes the cause. It does not cover land, landscaping for its own sake, or excluded perils such as flood or earth movement unless you buy separate coverage.
How are Coverage B and Coverage C limits usually set?
Coverage B is often 10% of Coverage A for other structures; Coverage C is often 50% of Coverage A for personal property. Those are starting points, not targets. Increase Coverage B when detached buildings exceed the default, and set Coverage C from a room-by-room inventory including off-premises and scheduled items.
Does Coverage C cover the same causes of loss as Coverage A?
Not on HO-3. Coverage A is open perils on the dwelling; Coverage C is named perils on contents. A loss to the house and contents from the same event can be covered under A but denied or disputed under C if the cause is not a listed peril for personal property.
What does Coverage D pay for?
Coverage D pays additional living expense and related loss-of-use costs when a covered property loss makes the home uninhabitable, subject to policy limits and time periods. It does not pay mortgage payments or costs you would have incurred anyway. Flood and earthquake displacement are not covered under standard HO-3 Coverage D unless those perils are insured.
What happens if Coverage A is too low?
An inadequate Coverage A limit can trigger coinsurance on partial losses, reducing every payment by the same proportion. In a total loss, you may simply receive the limit on the declarations page, which may be far below rebuild cost. Extended or guaranteed replacement cost endorsements help only when purchased and when you meet their conditions.
How do commercial property Coverages A and B differ from homeowners A–D?
Commercial Coverage A is buildings; Coverage B is business personal property. Loss of income and extra expense are handled on separate business income forms, not Coverage D. Homeowners Coverage C and D have no direct commercial equivalent on the same dec page—you match limits to building, contents, and continuity exposure separately.