I've been at enough project financing tables to know how this goes. The developer has done the work. The structural system is solid, the enclosure strategy is documented, the schedule is credible. Then the lender's insurance requirement lands. And what the market can actually deliver doesn't match what was modeled.

This happens with mass timber more than people talk about publicly. The industry has made real progress on structural engineering, code compliance, and cost certainty. Insurance hasn't kept pace. That's a project risk, and in some cases, a deal risk.

Carriers Are Not Aligned

The mass timber insurance market isn't monolithic. Carriers are pricing the same structural system at meaningfully different rates depending on how they've internally classified the risk. Some treat mass timber like heavy timber, which historically carries favorable fire resistance ratings and lower premiums. Others treat it as a new and unproven system and price accordingly. A few won't write it at all.

That inconsistency isn't irrational from the carrier's perspective. Mass timber has limited claims history. The built inventory is still small relative to conventional construction. Actuarial models need data. Data takes time. In the meantime, underwriters are making judgment calls, and those calls vary.

For a developer, that variance creates a planning problem. You can model insurance cost based on a carrier conversation early in the development process and get a number that looks reasonable. By the time you're closing financing, the market has shifted or a different underwriter is on the file and the number is different. Sometimes meaningfully different.

What's Actually Being Priced

Fire is the obvious one. Mass timber's fire performance has been validated in ways that should be reassuring to carriers. The IBC now recognizes mass timber through Type IV construction types A, B, and C. The first 3-hour fire test for high-rise mass timber cleared a major threshold. The engineering is sound.

But fire isn't the whole story. Carriers are also pricing duration of construction exposure, moisture vulnerability during erection, and the limited claims history for completed mass timber buildings. Each of those factors creates uncertainty, and uncertainty gets priced into the premium.

Moisture exposure during construction is worth particular attention. Mass timber is hygroscopic. CLT and glulam panels absorb moisture during erection, especially in climates with significant rainfall. If the enclosure sequence isn't managed tightly, you can introduce durability risk before the building is even complete. Carriers who understand this are asking questions about erection schedules, temporary weather protection plans, and the developer's moisture management protocol. Carriers who don't understand it may be writing coverage without fully pricing the exposure.

This connects directly to enclosure strategy as a risk variable. I've written about this at length in The Importance of the Building Enclosure. The enclosure isn't a finish. It's a control layer. And in mass timber, it also becomes an insurance risk management tool.

Where It Shows Up in the Pro Forma

The insurance gap surfaces in predictable places. Builder's risk during construction. Property insurance post-completion. And increasingly, the lender's specific coverage requirements, which may not align with what the broader market is offering for mass timber.

Builder's risk for mass timber construction can run significantly higher than conventional framing, particularly for projects in fire-exposed locations or with extended erection schedules. Some carriers require wrap-up programs that consolidate coverage across the project, which adds administrative complexity and cost. Others require third-party moisture monitoring during construction as a condition of coverage. That's not unreasonable, but it needs to be in the project budget from the start.

Post-completion, the long-term property insurance picture is still developing. There aren't enough mass timber buildings with five-plus years of operating history for the market to have confident data on long-term performance. Carriers are watching. The buildings performing well are quietly improving the market's perception. The ones with problems are quietly hardening it.

Developers are building faster than the risk transfer mechanisms can keep up. That's not a criticism of the insurance industry. It's a planning variable that mass timber developers need to account for.

What Disciplined Developers Are Doing

The teams getting this right are treating insurance as part of the development process, not a closing task. That means a few specific things.

Early broker engagement. Not just a quote, but a conversation about how the carrier is classifying the system, what documentation they'll require, and what underwriting questions will need answers. The broker who understands mass timber specifically is a different conversation than a generalist commercial real estate broker.

Documentation that speaks to carrier concerns. Moisture management plans, enclosure sequencing documentation, structural peer review letters, fire protection engineering reports. These aren't just construction documents. They're underwriting exhibits. A developer who can hand a carrier a well-organized package addressing the specific risk questions gets better engagement and usually better pricing.

Conservative insurance assumptions in the pro forma. Model the high end of the range, not the optimistic case. If the market comes in better, that's upside. If it comes in at the high end, you've accounted for it. This sounds obvious. It gets skipped more often than it should, especially when teams are trying to make deals pencil.

Understanding the lender's requirements before the lender asks. Some lenders have specific mass timber insurance requirements that aren't publicly documented. Asking early, before you're in exclusivity, avoids surprises during financing.

A Conversation the Industry Needs to Have

The broader mass timber industry has been focused, rightly, on structural engineering, cost certainty, and code development. Those were the right priorities. The code progress has been substantial. The cost conversations are maturing. Insurance is next.

The International Mass Timber Conference has sessions on financial feasibility and capital structure, but the insurance question sits underneath both of those and doesn't get its own agenda slot. That should change. The developers who have navigated these conversations successfully have institutional knowledge that would benefit the entire industry, and the carriers who are actively building mass timber expertise are worth identifying.

At Durata Advisory, risk structuring before material exposure is the core of what we do with development teams. The insurance gap in mass timber is an early-stage risk that often doesn't surface until financing, which is exactly the wrong time to discover it. Getting that conversation started at feasibility, not closing, changes the outcome.

The structural case for mass timber is strong. The construction logic is sound. The risk transfer infrastructure is catching up. Understanding where the gaps still exist is part of developing these projects with discipline.

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Frequently Asked Questions

Why is insurance a problem specific to mass timber and not conventional construction? It isn't a problem with the material. It's a problem with claims history. Conventional construction has decades of actuarial data. Mass timber has a fraction of that. Carriers are making judgment calls where they'd prefer statistical confidence, and judgment calls get priced conservatively. As the built inventory grows and buildings age without incident, the pricing will normalize. We're in the transitional period right now.

What drives the inconsistency between carriers? Two things primarily. First, internal classification: some carriers have filed mass timber under heavy timber, which has favorable historical loss data. Others treat it as a new and unproven system. Second, the level of mass timber expertise within each underwriting team. The carriers actively building expertise in this space are asking better questions and writing more competitive coverage. The ones without that expertise tend to either avoid it or price in a wide uncertainty margin.

What documentation helps most when engaging insurers early? Fire engineering analysis specific to the project, not generic industry test results. A construction moisture management plan showing how the enclosure sequence follows the structural erection. The structural engineer's connection documentation. And if available, reference letters from insurers on comparable completed projects. Carriers respond to specificity. Generic project descriptions get generic pricing.

When does the insurance gap typically surface in a development process? Almost always during financing. The lender's insurance requirements land, the developer discovers the available coverage is more expensive or more restrictive than what was modeled in the pro forma, and the deal has to be renegotiated or restructured under time pressure. That's the worst possible moment for a surprise. Engaging insurers at schematic design eliminates the surprise entirely.

Is builder's risk or long-term property insurance the bigger challenge? Both matter, but builder's risk during construction is where the immediate cost gap tends to show up. Long-term property insurance is improving as the built inventory grows. The construction phase, with its moisture exposure window and limited claims history for the erection process itself, is where carriers are most uncertain and pricing is most variable.

Does a better enclosure strategy actually affect insurance pricing? Yes, with carriers who understand mass timber. A documented moisture management plan, a tight enclosure sequence tied to the erection schedule, and third-party quality control during construction all reduce the exposure that makes carriers price conservatively. This is one reason enclosure strategy isn't just a building performance question. It's a risk transfer question.