Other Structures Coverage in Homeowners Insurance
Other structures coverage is a standard component of homeowners insurance policies that extends protection beyond the main dwelling to detached buildings and features on the property. This page explains how the coverage is defined, how its limits are calculated, the types of property it applies to, and where its boundaries lie. Understanding this coverage prevents gaps that can leave property owners responsible for significant uninsured repair or replacement costs after a covered loss.
Definition and scope
Other structures coverage — designated as Coverage B in the standard homeowners policy framework established by the Insurance Services Office (ISO) — applies to structures on the insured property that are separated from the dwelling by a clear space, or connected to it only by a fence, utility line, or similar connection. The ISO HO-3 policy form, which is the most widely used residential policy form in the United States, defines the dwelling itself under Coverage A and separately carves out Coverage B for these detached structures.
Structures typically included under Coverage B:
- Detached garages
- Fences and walls
- Driveways and walkways (in some forms)
- Guest houses or in-law cottages
- Sheds and storage buildings
- Gazebos and pergolas
- Swimming pool enclosures and pool equipment structures
- Barns (on residential properties)
Coverage B does not apply to land, landscaping, or the dwelling itself. It also excludes structures used for business purposes or rented to someone other than a tenant of the main dwelling — a boundary explored further in the decision boundaries section below.
For a complete overview of how Coverage B fits within the broader policy architecture, see Homeowners Insurance Policy Structure.
How it works
The Coverage B limit is not independently negotiated in most standard policies. Under the ISO HO-3 form, the default Coverage B limit is set at 10% of the Coverage A (dwelling) limit (ISO HO-3, Coverage B provision). If the dwelling is insured for $400,000 under Coverage A, Coverage B automatically provides $40,000 for other structures — without a separate premium line in most cases.
This percentage-based structure has two practical effects:
- Automatic scaling: As dwelling coverage increases, Coverage B scales upward proportionally, which can be beneficial when inflation adjustments or guaranteed replacement cost endorsements raise Coverage A.
- Fixed ceiling risk: Property owners with high-value outbuildings — a $60,000 workshop or a $50,000 pool house, for example — may find the default 10% ceiling insufficient relative to actual replacement cost.
Coverage B follows the same peril structure as the main dwelling coverage on the same policy. On an HO-3 form, the dwelling (Coverage A) is covered on an open-perils basis, meaning all causes of loss are covered unless specifically excluded, while personal property (Coverage C) is covered on a named-perils basis. Coverage B under HO-3 is also covered on an open-perils basis, subject to the same exclusions listed in the policy — including flood, earthquake, and intentional acts.
The valuation method applied to Coverage B losses matters significantly. Policies may settle other structures claims at actual cash value (ACV) — replacement cost minus depreciation — or at replacement cost value (RCV). The distinction can be substantial for older outbuildings. A 20-year-old shed with a replacement cost of $8,000 might settle at $3,500 under ACV after depreciation. See Replacement Cost vs Actual Cash Value for a detailed treatment of how these two valuation methods operate in practice.
Deductibles apply to Coverage B losses in the same manner as Coverage A losses — a standard deductible is subtracted from the covered loss amount before payment is issued. The mechanics of deductible application are covered at Home Insurance Deductibles.
Common scenarios
Detached garage damage: This is the most frequent Coverage B claim. Fire, windstorm, hail, and vehicle impact are the leading causes of detached garage losses. Because Coverage B follows the same open-perils structure as the dwelling on HO-3 forms, fire and wind damage to a detached garage is covered without the policyholder needing to demonstrate which specific peril caused the loss.
Fence and wall losses: Fences are specifically listed as other structures in ISO policy forms. Wind and falling tree damage to fencing is a common claim. Notably, flood damage to fences is excluded on standard policies, consistent with the broader home insurance exclusions framework. Flood coverage for all structures on a residential property requires a separate policy through the National Flood Insurance Program (NFIP), administered by FEMA.
Guest cottages and accessory dwelling units (ADUs): A detached guest house used exclusively by family members or occasional guests qualifies under Coverage B. However, if the unit is rented — even occasionally through a short-term platform — the structure may fall outside Coverage B protection under the business-use and rental exclusions. This scenario intersects with Short-Term Rental Insurance considerations.
Swimming pools and pool structures: The pool structure itself (the shell, surrounding deck, and any attached enclosure) may qualify for Coverage B, but the pool's water, pumping equipment, and plumbing are subject to policy-specific language. Liability associated with a pool is a separate concern handled under Coverage E (liability), addressed at Trampoline and Pool Liability Coverage.
Agricultural structures on residential parcels: Small barns on residential properties are generally covered under Coverage B. Large operational farm structures may require a separate farm policy, as the residential HO forms are designed for dwellings rather than working agricultural operations.
Decision boundaries
Three key thresholds determine whether a structure qualifies for Coverage B, whether the default limit is adequate, and whether an endorsement is required.
Threshold 1: Attachment and connection
A structure physically attached to the main dwelling by more than a fence, utility line, or similar connection is typically classified as part of the dwelling (Coverage A), not an other structure. A breezeway-connected garage may qualify under Coverage A depending on the insurer's interpretation. Policy language and insurer guidelines govern this determination, and individual underwriters may classify borderline structures differently.
Threshold 2: Business use and rental exclusion
ISO HO-3 policy language excludes Coverage B for structures "used in whole or in part for business" or rented to anyone other than a tenant of the dwelling. A detached office used exclusively for remote work presents an ambiguous case — some insurers treat home offices as excluded business structures; others do not. The Home Business Insurance Endorsements page covers available modifications for business-use structures.
Threshold 3: Limit adequacy
When the value of other structures on a property exceeds the default 10% Coverage A limit, policyholders may request a Coverage B limit increase. Not all insurers offer this as a standalone endorsement; some accomplish it through a blanket increase in Coverage A, which proportionally raises Coverage B. The Insurance to Value Requirements framework governs how insurers evaluate whether dwelling coverage is adequate, and the same principles apply when assessing Coverage B sufficiency.
A comparison of Coverage B under two common policy forms illustrates practical differences:
| Feature | HO-3 (Special Form) | HO-1 (Basic Form) |
|---|---|---|
| Peril basis (Coverage B) | Open perils | Named perils only |
| Default Coverage B limit | 10% of Coverage A | 10% of Coverage A |
| Valuation default | ACV (RCV by endorsement) | ACV |
| Business-use exclusion | Yes | Yes |
| Flood exclusion | Yes | Yes |
The HO-1 Basic Form, now rarely issued in the standard market, covers other structures only against a short list of named perils — fire, lightning, explosion, windstorm, hail, smoke, vandalism, theft, and vehicle damage — leaving structures unprotected against collapse, weight of ice and snow, and other causes covered by the HO-3. This distinction underscores why Home Insurance Policy Forms HO-1 through HO-8 selection affects Coverage B protection meaningfully.
Property owners with high-value outbuildings, income-producing accessory structures, or business-use buildings should treat Coverage B as a starting point rather than a complete solution, evaluating whether endorsements, separate policies, or Coverage A adjustments are warranted based on an accurate assessment of replacement cost.
References
- Insurance Services Office (ISO) — Policy Forms and Coverage
- National Flood Insurance Program (NFIP) — FEMA
- National Association of Insurance Commissioners (NAIC) — Homeowners Insurance Guide
- FEMA Flood Map Service Center
- Insurance Information Institute (Triple-I) — Homeowners Insurance Basics