Insuring a home renovation or addition in Massachusetts: builder's risk and coverage gaps.

Why a standard homeowners policy stops covering you mid-renovation

A renovation or addition is not a cosmetic change from an underwriting standpoint. It’s a change in risk. The Massachusetts Division of Insurance’s guidance on accessory dwelling units states plainly that you should notify your insurer before construction begins, because modifications, additions, or new construction change the risk profile of the property, and the insurer always retains the right to non-renew coverage afterward if the property no longer meets its underwriting guidelines. That’s not a hypothetical. It’s baked into how the policy works: insurers underwrite the house they insured, not the house you’re about to build.

Massachusetts law gives you some procedural protection here. An insurer is not required to write or renew a homeowners policy, but if it chooses not to renew, it must notify you at least 45 days before the policy’s expiration date, by first-class mail. Insurers cannot base a decline, non-renewal, or cancellation decision on the specific prohibited criteria set out in M.G.L. c. 175, § 4C, though underwriting guidelines otherwise vary company to company. None of that changes the core fact: if you don’t tell your carrier about the work, you may be carrying a policy that no longer matches the risk, and you won’t find out until a claim or a renewal review exposes it.

The Division of Insurance also flags a specific number to check before you sign a contract: the dwelling limit, Coverage A, on your Declarations page. Before renewing each year, homeowners should understand the full cost of rebuilding, including renovations or additions, and that figure should reflect the finished project, not the house as it stood before the permit was pulled.

Builder’s risk insurance: what it actually protects and how a mid-project loss gets paid

For anything beyond a minor repair, a standard homeowners policy generally isn’t the right instrument for construction-phase risk. The Insurance Information Institute recommends looking into a builder’s risk policy, also known as a course-of-construction policy, for bigger renovation projects. It’s available either as a stand-alone policy or as an add-on to your existing homeowners policy.

This coverage generally protects the home from damage incurred during construction, including wind and rain, theft of materials such as carpeting, tile, or wood, and vandalism. It does not cover the contractor’s own equipment; that’s the contractor’s problem, and it’s a good reason to verify their coverage separately. Massachusetts regulation 211 CMR 10.02 defines this more formally: Builders Risks or Installation Risks coverage protects the interest of an owner, seller, or contractor against loss or damage to machinery, equipment, building materials, or supplies while they’re being used with and during the course of installation, testing, building, renovating, or repairing. Under that same regulation, if the policy is written for the owner’s account, coverage ends upon completion and acceptance of the work; different completion terms apply if it’s written for a seller or contractor.

One mechanic worth understanding before a loss happens: builder’s risk-type coverage typically pays proportionally to how far along the project is. If a policy is written for replacement value and a covered peril destroys the building when it’s half finished, the policy pays half the value the completed building would have had. That’s a meaningfully different outcome than a finished-house claim, and it’s why the coverage amount needs to track the project’s completed value, not its current, partially-built value.

The gap: additions, new construction, and what falls outside the HIC law

The Home Improvement Contractor law, M.G.L. c. 142A, requires contractors doing work on an existing, owner-occupied residential property with one to four units to register as an HIC. That registration comes with real consumer protections: arbitration through OCABR and access to the Guaranty Fund.

But the law has a scope gap that matters directly for renovation and addition projects. OCABR states it explicitly: new construction, buildings with more than four units, investment, vacation, or secondary properties, and homes not located in Massachusetts are not covered under this law. An addition to your house may straddle that line depending on how the work is classified, which is exactly why verifying credentials matters before signing anything, a topic covered in more depth in the guide to /guides/massachusetts-contractors-general-liability-license-bond/.

There’s also a licensing distinction that trips people up. HIC registration alone covers ordinary repairs, like exterior painting, wallpapering, or repairing existing decking. Larger projects, such as building a deck or an addition to an existing home, require a Construction Supervisor License, a separate and non-interchangeable credential. Some structural work, like a kitchen renovation, may require both a CSL and HIC registration, though not necessarily held by the same person. If you’re hiring for an addition, ask specifically about the CSL, not just the HIC number.

Verifying your contractor before you sign anything

Before work starts, ask to see the contractor’s insurance. The Insurance Information Institute recommends requesting copies of both a commercial business or general liability policy and a workers’ compensation policy; if a contractor won’t verify coverage, consider hiring someone else. OCABR’s homeowner resources page echoes this: ask to see the HIC identification card and request proof of liability and workers’ compensation insurance before hiring.

This isn’t optional paperwork on permits, either. A standard Massachusetts building-permit application for a one- or two-family dwelling requires a Workers’ Compensation Insurance Affidavit under M.G.L. c. 152, § 25C(6) before a permit will be issued. Building permits, contracts, and advertising for residential contracting work must also carry the contractor’s active HIC registration number.

Get everything in writing. State law requires home improvement contracts for work estimated at $1,000 or more to be in writing, with certain required provisions. That written contract isn’t a formality: it’s the document that gates your access to HIC arbitration and the Guaranty Fund if things go wrong. It should also have the contractor agreeing to pull the building permit, since permit ownership matters later for eligibility.

If something goes wrong: arbitration, the Guaranty Fund, and its dollar limits

The HIC law, created in 1992, built in an arbitration program and a Guaranty Fund to compensate consumers for unpaid judgments against contractors. The current cap is $25,000. That’s a legislative increase from an earlier, lower cap of $10,000 that still appears in an older regulation, 201 CMR 14.00, so don’t be surprised if you see both figures referenced; the current cap is $25,000, and the fund compensates actual loss up to that amount, which may differ from the arbitration award or judgment itself.

Eligibility has real conditions. The contract must cover work on a pre-existing one-to-four-family Massachusetts residence that’s your primary residence. A court judgment or arbitration award must already exist, with reasonable collection efforts exhausted. And the contractor, not the homeowner, must have secured the building permit. If you pulled the permit yourself, or hired someone unregistered, you may be locked out entirely: OCABR and the standard building-permit application both warn that unregistered-contractor work forfeits both arbitration and Guaranty Fund eligibility. HIC registration itself must be renewed every two years, with a $150 fee plus a Guaranty Fund fee of $100 to $500 based on employee count, so an expired registration can create the same gap as no registration at all.

Additions, ADUs, and permanent coverage changes after the work is done

Once the project wraps, the insurance conversation shifts from construction risk to permanent dwelling value. If a basement or attached garage is converted into an accessory dwelling unit, the insurer will likely treat it as part of the primary structure and raise the dwelling coverage limit. If you build a detached ADU instead, you’ll likely need an endorsement or separate limits to cover it. If you plan to rent the ADU, tell your carrier; renting changes the property’s risk characteristics, and you may need landlord coverage for property damage, liability, and loss of rental income.

Expect a premium increase either way. The Division of Insurance notes that building an ADU will most likely raise your premium due to increased replacement cost, added liability exposure, and potential rental activity, though the size of the increase varies by insurer and by the ADU’s size and use. If your carrier declines to continue coverage after a major addition or ADU, two fallback paths exist: the surplus lines market through a licensed broker, or the Massachusetts Property Insurance Underwriting Association, the FAIR Plan, the state’s insurer of last resort for properties that can’t secure coverage in the standard market. Reviewing your policy annually against these changes is worth doing systematically; see the general framework in /guides/how-home-insurance-works-in-massachusetts/.

Closing liability gaps during the project: DIY help, pools, and umbrella coverage

If friends or family are helping with a DIY project, liability exposure is real. The Insurance Information Institute recommends raising the no-fault medical payments coverage on your homeowners policy so injury-related bills can be submitted directly, which lessens the chance of being sued. It’s also worth asking about an excess or umbrella liability policy as a cost-effective way to increase overall liability protection during the project.

Certain additions raise the stakes further. A swimming pool or hot tub added during a renovation is considered an attractive nuisance that can increase lawsuit vulnerability. A major life or property change tied to the renovation, like starting a home-based business or having an elderly relative move in, may call for reevaluating other coverage entirely, not just the dwelling limit.

Once the work is done, forward your records and receipts to your insurer so it can accurately reassess your coverage needs. Consider a floater or endorsement for any expensive items you purchased during the project, since that provides higher individual coverage than a standard policy allows. None of this is automatic; it happens because you flagged the change, not because the insurer noticed on its own.