Dwelling Coverage vs. Other Structures: The Attached vs. Detached Rule

When it comes to granny flat home insurance, the single most important factor is whether your unit is attached or detached from your main home. This one distinction determines which part of your homeowners policy applies — and how much protection you actually have.

Attached in-law suites (those sharing a wall, ceiling, or foundation with the primary residence) are generally treated as part of the main dwelling and fall under Coverage A (Dwelling Coverage). This means the suite is protected under the same structural coverage as your home — as long as your policy limits are high enough to account for the added square footage and features.

Detached granny flats, on the other hand, fall under Coverage B (Other Structures Coverage). This is a significant distinction because other structures coverage is typically capped at just 10% of your dwelling coverage limit. For example, if your home is insured for $400,000, your detached granny flat would only have $40,000 in coverage — likely far below what it would cost to rebuild a fully finished living unit.

Does home insurance cover a granny flat automatically? In most cases, partially — but rarely fully without a coverage update.

Liability Concerns: Family Members vs. Paying Renters

Who lives in your granny flat matters enormously for liability insurance purposes. Insurers treat these two scenarios very differently.

When Family Members Occupy the Unit

If a parent, adult child, or other relative lives in your in-law suite rent-free, your standard homeowners policy typically provides liability coverage for injuries or incidents that occur in that space. Personal liability coverage (usually $100,000 to $300,000) can help cover medical bills or legal costs if someone is injured on the property.

However, even with family occupants, you should review your personal liability limits. A slip-and-fall accident or structural injury can generate costs that easily exceed a standard limit. Adding an umbrella insurance policy that extends coverage to $1 million or more is a smart and affordable safeguard.

When You Rent to Tenants

The moment you collect rent from a tenant — even occasionally — your standard homeowners policy becomes inadequate. Insurers classify rental activity as a business operation, and most homeowners policies explicitly exclude tenant-related incidents and tenant guest injuries.

Without the right coverage, you could face:

• Out-of-pocket legal defense costs if a tenant or their guest is injured
• No coverage for tenant-caused property damage
• No loss of rental income if the unit becomes uninhabitable due to a covered event

Many landlords now carry liability limits of $1 million or higher, often paired with an umbrella policy for additional protection. Requiring tenants to carry their own renters insurance is also widely recommended — it helps transfer some financial risk away from your policy.

When You Need a Separate Landlord Policy

Insuring a granny flat as a rental requires a different type of policy entirely. A landlord insurance policy (DP-3) is designed specifically for income-generating rental properties and covers risks that homeowners policies exclude.

Key Triggers for Getting a Landlord Policy

• You collect rent from a tenant — short-term or long-term
• The unit has a separate address or title from the main home
• The unit has separate tenants from the primary dwelling
• The ADU is freestanding or subdivided as a distinct property

What a Landlord Policy Covers for a Granny Flat

If you live in the main home and rent only the granny flat, you'll typically need both a standard homeowners policy (for your residence) and a landlord policy or endorsement (for the rental unit). Some insurers can bundle these under one policy if both structures are on the same property title.

Learn more about guest house and ADU coverage to understand how other structures on your property are treated under standard homeowners insurance.

Increasing Coverage Limits for Finished Living Spaces

A fully finished in-law suite — complete with a kitchen, full bathroom, separate entrance, and living space — dramatically increases the rebuild value of your property. If your policy limits haven't been updated since the suite was built or finished, you're likely underinsured.

Kitchen & Full Bathroom Considerations

A granny flat with a full kitchen and bathroom adds significant rebuild costs due to:

• Plumbing and electrical work required for kitchen appliances and bathroom fixtures
• Cabinetry, countertops, and appliances that must be replaced in a total loss
• Flooring, tile, and finish work that drives up square-footage rebuild costs

These features can add tens of thousands of dollars to your total rebuild exposure. Yet most homeowners never update their dwelling coverage after completing a suite addition.

Steps to Properly Update Your Coverage

1. Notify your insurer as soon as construction is complete or when you convert a space into a finished living unit
2. Request a rebuild cost appraisal to determine the accurate replacement value of the additional structure
3. Raise your Coverage A limit (for attached suites) or request a higher Coverage B limit or separate coverage (for detached units)
4. Review your liability limits — finished living spaces that are occupied increase liability exposure significantly
5. Ask about ordinance or law coverage — if your granny flat was built under older codes, rebuilding after a loss may require costly code upgrades not covered by a basic policy

For a deeper dive into how finished vs. unfinished structures affect your coverage, check out this guide on ADU and guest house insurance.

Frequently Asked Questions

Does home insurance automatically cover an attached in-law suite?

Not fully — and this surprises many homeowners. While an attached in-law suite typically falls under your dwelling coverage (Coverage A), your policy limits are not automatically adjusted to reflect the suite's added rebuild value. You must notify your insurer so they can reassess your total insured value and update your limits. Failing to do so leaves you underinsured in the event of a major loss.

What's the difference between "other structures" and "dwelling" coverage for a granny flat?

Dwelling coverage (Coverage A) protects the main structure of your home, including any attached additions like an in-law suite. Other structures coverage (Coverage B) applies to separate, detached buildings like a standalone granny flat or guest house. The key issue is that Coverage B defaults to just 10% of your dwelling limit — often far too low to fully rebuild a finished detached ADU.

Do I need a landlord policy if I only charge my parents or family a small amount of rent?

Yes — if you collect any form of rent, most insurers will classify the arrangement as a rental activity, which falls outside standard homeowners policy coverage. Even nominal rent can void your liability and property protections for that unit. It's best to speak with your insurer directly about your situation and consider a landlord endorsement or standalone rental policy.

What liability risks come with renting out a granny flat?

If a tenant or their guest is injured on your property and you only have a standard homeowners policy, you may be entirely responsible for medical bills and legal defense costs out of pocket. Standard personal liability coverage also does not cover tenant-caused damage to the structure. Landlord policies are specifically designed to address these risks with dedicated liability limits, often $500,000 to $1 million or higher.

How does a full kitchen affect my granny flat insurance coverage?

A full kitchen — with plumbing, appliances, and cabinetry — significantly increases the rebuild value of your in-law suite and can also affect how your insurer classifies the space. Some carriers may treat a unit with a full kitchen as a separate dwelling rather than an extension of the main home, which can impact coverage classification and limits. Always disclose full kitchen and bathroom features to your insurer and make sure your rebuild coverage reflects the true cost of replacing those finishes.