Answer-first summary: Tariffs on imported steel, aluminum, lumber, and other construction materials directly raise the replacement cost of buildings under construction — pushing builders risk insured values 10–25% higher than pre-tariff baselines in many markets as of mid-2026. Underinsurance becomes the primary risk when projects are valued at permit time but tariff-driven cost increases accumulate through the build. Who this is for: General contractors, developers, and project owners buying or renewing builders risk coverage in the current tariff environment.
TL;DR / Key Takeaways
- Tariff-driven material cost increases (steel +20–40%, softwood lumber +15–25% at peak tariff levels) inflate the completed-value basis that builders risk policies use to set limits.
- Builders risk is almost always written on a completed-value (replacement cost) basis — if your insured value is stale, a partial loss triggers the coinsurance penalty and leaves you holding the gap.
- Schedule of values updates mid-project are possible but require insurer approval; do this proactively when material costs spike materially (typically >10%).
- Property appraisals on existing commercial buildings are equally affected — replacement cost new (RCN) estimates used by insurers rise with tariff-inflated material prices, pushing property premiums up and making RCV vs. ACV elections more consequential.
- An independent agent who shops multiple markets can negotiate agreed-value endorsements and inflation guard provisions that protect you through a volatile build.
Why Tariffs Drive Up Builders Risk Insured Values
Builders risk policies cover a structure during the course of construction. The insured value — also called the "completed value" — must equal the total projected cost of the completed project, including all materials and labor. When tariffs raise the cost of core construction inputs, that completed value rises too.
The 2018–2019 Section 232 tariffs on steel and aluminum, and Section 301 tariffs on a broad range of Chinese goods (including certain building products), provided a dry run. Markets saw:
- Structural steel costs increase 20–40% during peak 2018 tariff periods.
- Softwood lumber (already volatile due to Canadian countervailing duties) spike sharply, with Random Lengths framing lumber futures at times exceeding $1,200 per thousand board feet vs. pre-tariff baselines near $350–$400.
- Mechanical, electrical, and plumbing (MEP) components — including copper wire, HVAC equipment with imported compressors, and PVC/CPVC piping — all experiencing cost inflation.
In 2025–2026, a second wave of broad tariffs across multiple trading partners has reproduced similar dynamics. A contractor who locked in a GMP (guaranteed maximum price) contract at 2024 material costs now faces cost-to-complete figures that exceed the original insured value on the builders risk policy.
The Coinsurance Problem in Plain Terms
Most builders risk policies include a coinsurance clause — typically 100%. If the actual replacement cost at the time of loss exceeds the policy limit, the insured is treated as a co-insurer on the shortfall.
Formula: Recovery = (Amount of Insurance / Required Insurance) × Loss
Example: A policy written for $4 million on a project whose completed value has risen to $5 million due to tariff-driven cost increases. At 100% coinsurance, recovery on an $800,000 partial loss = ($4M / $5M) × $800,000 = $640,000 — a $160,000 out-of-pocket gap that pure tariff inflation created.
How Tariffs Affect Property Replacement Cost Values on Existing Buildings
Builders risk is not the only exposure. Commercial property policies insuring existing buildings also rely on replacement cost new (RCN) estimates — the cost to rebuild the structure from scratch using current labor and material prices. When tariffs inflate those input costs, RCN rises even though the building itself hasn't changed.
Appraisal firms and carrier valuation models (such as Marshall & Swift/CoreLogic) periodically update their cost databases to reflect market pricing. After tariff waves, these models reset upward, which can trigger:
- Premium increases at renewal as insurers reprice to the higher limit.
- Insurer-mandated limit increases — carriers who track coinsurance compliance may require you to raise your limit.
- Coverage gaps for policyholders who decline to raise limits — electing a stale RCN to save premium is a common and costly mistake.
Tariff Impact by Material Category: A Cost Reference Table
| Material / System | Primary Tariff Driver | Approximate Cost Impact (2025–2026) | Effect on Insured Value |
|---|---|---|---|
| Structural steel (domestic) | Section 232 (25%) | +15–30% vs. pre-tariff baseline | Raises completed value for steel-framed commercial buildings |
| Softwood lumber | Canadian CVD/ADD duties, broad tariff waves | +20–40% at peak; volatile | Raises framing costs for wood-framed residential/light commercial |
| Aluminum (windows, curtainwall, roofing) | Section 232 (10–25%) | +10–20% | Higher envelope costs; affects both new construction and reroofing values |
| HVAC equipment | Section 301 / broad tariffs on Chinese components | +10–25% | MEP budgets escalate; often underrepresented in early project estimates |
| Copper wire & conduit | Tariffs + commodity volatility | +15–30% | Electrical budgets outpace original GMP figures |
| Plumbing fixtures & fittings | Section 301 (various) | +10–20% | Hard to predict; sourcing substitutions affect quality comparables |
| Concrete / masonry (largely domestic) | Minimal direct tariff exposure | +5–10% (energy/fuel cost inflation, not direct tariff) | Moderate impact; watch aggregate and rebar pricing |
Cost impact ranges are illustrative estimates based on publicly available market reporting as of mid-2026 and will vary by region, procurement strategy, and trade partner sourcing. Confirm current costs with your contractor and insurer.
How to Update Your Builders Risk Coverage When Material Costs Spike: A 5-Step Process
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Reassess your schedule of values. Work with your GC or cost estimator to reforecast the total cost to complete using current (not contract-date) pricing for all major line items. Do this at every major procurement milestone.
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Identify the gap. Compare the revised completed-value estimate to the current builders risk policy limit. If the gap exceeds 5–10%, a limit endorsement is warranted. At 10%+ variance, the coinsurance exposure becomes financially meaningful.
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Notify your broker immediately. Request a limit increase endorsement from the insurer. Most carriers will accommodate mid-term limit changes with a pro-rata additional premium for the remaining policy term. Waiting until renewal is a mistake if cost inflation is happening now.
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Ask about an agreed-value endorsement. An agreed-value (AV) endorsement suspends the coinsurance clause in exchange for the insurer acknowledging the stated value as adequate. This eliminates the coinsurance trap — critical in a volatile-cost environment.
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Revisit at each major milestone. Builders risk is dynamic. Repeat the schedule-of-values check when framing is complete, when MEP rough-in is complete, and 60 days before substantial completion. Log the check with your broker to document diligence.
Real-World Illustrative Example: Mixed-Use Development in Texas
Scenario: A developer in Dallas, Texas, breaks ground in Q3 2024 on a $12 million mixed-use building — five stories, steel frame, brick veneer, 32 residential units over ground-floor retail. The builders risk policy is issued at a $12 million completed value, 100% coinsurance, 12-month policy term.
By Q1 2025, structural steel costs in the Dallas market have risen approximately 22% from the 2024 bid date due to Section 232 tariff effects and spot-market tightening. MEP subcontractors are coming in 15% over original allowances due to tariff-impacted copper and HVAC equipment costs. The revised cost-to-complete is now estimated at $13.8 million.
The developer has not notified the insurer. In March 2025, a fire during framing causes $2.2 million in damage.
Claim recovery under coinsurance formula: - Required insurance: $13.8M - Insurance carried: $12M - Loss: $2.2M - Recovery: ($12M / $13.8M) × $2.2M = $1.91 million - Out-of-pocket gap: $290,000 — entirely attributable to failure to update the insured value after tariff-driven cost escalation.
Had the developer requested a mid-term limit endorsement to $13.8M, the additional premium for the remaining 9-month term would have been approximately $4,000–$8,000 [estimate; varies by carrier and risk]. The $290,000 gap makes that a stark comparison.
This is an illustrative scenario for educational purposes. Actual claim outcomes depend on specific policy language, carrier, and circumstances.
FAQ: Tariffs, Builders Risk, and Property Insurance
Q: Does my builders risk policy automatically adjust for tariff-driven cost increases? A: No. Standard builders risk policies do not include automatic inflation adjustment for mid-term cost increases. Some policies include an "inflation guard" provision that adds a small percentage (typically 4–8% annualized) to the limit over the policy term, but this is rarely adequate to track sharp tariff-driven spikes. You must proactively request a limit endorsement.
Q: What happens if my project goes over budget due to tariff costs — am I covered for the overrun? A: Builders risk covers physical loss or damage to the structure and materials; it does not cover cost overruns, schedule delays, or budget shortfalls as standalone losses. If a covered peril (fire, windstorm, theft) causes damage, the policy pays the cost to repair or rebuild — but only up to the insured limit and subject to coinsurance. The coverage gap caused by an inadequate limit is not itself an insured loss.
Q: How do tariffs affect my commercial property insurance at renewal? A: At renewal, your insurer will use current replacement cost valuation models — which are updated to reflect tariff-inflated material prices. Expect your recommended insured value (and therefore premium) to rise at renewal if you haven't already adjusted limits. Declining the increase to hold premium flat creates a coinsurance gap on existing property coverage as well.
Q: Are soft costs (architect fees, permits, interest) affected by tariff delays? A: Indirectly. Tariff-related supply chain delays extend project timelines, increasing soft costs like construction loan interest, extended general conditions, and A&E fees for redesign. Builders risk "soft costs" or "delay in opening" endorsements can cover some of these, but coverage terms vary widely by carrier and must be specifically purchased. Discuss this with your broker before binding.
Q: Can I buy builders risk on a "cost-plus" project without knowing the final value? A: Yes, but it requires more active management. Insurers typically allow a reporting-form or schedule-of-values approach on cost-plus projects. You report values at defined intervals and pay premium accordingly. In a tariff-volatile environment, the reporting frequency should be increased — monthly or at each procurement milestone rather than quarterly.
Q: Do tariffs affect inland marine coverage on materials in transit or stored off-site? A: Yes. Builders risk typically covers materials at the job site; materials stored off-site (staging yards, warehouses) or in transit may require a separate inland marine or installation floater. Tariff-inflated material values mean the value of materials in transit is higher — review sublimits on off-site/in-transit coverage to ensure they reflect current pricing.
Q: Will my carrier drop me if I keep requesting limit increases mid-term? A: Legitimate mid-term limit endorsements driven by documented cost escalation are a normal underwriting transaction. Carriers understand construction cost volatility, especially in the current tariff environment. Proactive communication with substantiated revised cost estimates is viewed favorably compared to discovering underinsurance at claim time.
Q: Is there a tariff-specific endorsement or rider I should ask for? A: There is no standard "tariff endorsement" in the ISO builders risk form. The tools to manage this exposure are: (1) agreed-value endorsement to waive coinsurance, (2) higher automatic inflation guard, (3) scheduled limit increase endorsements tied to milestones, and (4) reporting-form policies for long-horizon projects. Ask your broker to structure one or more of these into your placement.
Why Morrow for Builders Risk in a Tariff Environment
1. Independent access to multiple carriers. Morrow is an independent commercial P&C agency, not captive to one carrier's appetite. When tariff volatility affects underwriter capacity, Morrow shops admitted and E&S markets to find the coverage structure — agreed-value endorsements, soft costs, delay coverage — that fits your project.
2. Proactive schedule-of-values reviews. Morrow's construction insurance team builds mid-term limit review checkpoints into every builders risk placement. You don't have to remember to call us when steel prices jump — we flag it.
3. Specialization in construction and contractor risk. Beyond builders risk, Morrow places the full construction insurance tower: general liability, commercial auto, umbrella, inland marine/installation floaters, and contractors pollution liability. Tariff impacts ripple across all of these, and coordinated placement prevents gaps and overlaps.
4. Real claims advocacy. When a coinsurance clause could be applied against you at claim time, you want a broker who will review the schedule of values proactively and document the insured-value basis in the underwriting file. Morrow's claims advocacy means we are in your corner before a loss, not just after.
5. Fast COI and certificate turnaround. Construction projects move fast. Morrow provides rapid certificate-of-insurance turnaround so lenders, GCs, and owners aren't waiting on paperwork while your project schedule ticks.
Get a Quote
Ready to make sure your builders risk limits reflect today's tariff-driven costs? Contact Morrow for a coverage review and competitive quote. We'll assess your current insured value, identify coinsurance exposure, and structure a placement that protects you through the build.
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Morrow (Afthonea Inc., DBA Morrow) is a licensed independent commercial P&C insurance agency. [Morrow to confirm: licensed states list, NPN, carrier appointments.] Carriers represented include admitted and E&S markets. [Morrow to confirm: specific carrier names for disclosure.]
Related Resources
- Builders Risk Insurance: Complete Guide for Contractors and Developers
- Commercial Property Insurance: Replacement Cost vs. Actual Cash Value
- Construction Insurance Cost Guide: What Contractors Pay in 2026
- Inland Marine and Installation Floater Coverage
- General Contractor Insurance Requirements by State
Author: Jordan Reyes, CPCU, CIC — Commercial Lines Coverage Specialist, Morrow. Jordan has 12 years of experience structuring builders risk and commercial property programs for developers, general contractors, and specialty trades.
Published: June 2026 | Last updated: June 2026
Sources: - Insurance Information Institute (III) — Construction and Builders Risk Coverage - CIAB (Council of Insurance Agents & Brokers) — Commercial P&C Market Reports, 2024–2025 - U.S. International Trade Commission (USITC) — Section 232 and Section 301 tariff schedules - CoreLogic / Marshall & Swift — Building Cost Index updates, 2025–2026 - ISO (Verisk) — Commercial Lines builders risk and commercial property policy forms and circulars - Random Lengths — Framing lumber futures pricing data - National Association of Insurance Commissioners (NAIC) — A Consumer's Guide to Home Insurance (replacement cost methodology)