Mass‑timber has shifted from niche experiment to a mainstream structural option in the American West. Code changes that now permit timber towers up to 18 stories have opened a robust market, but those same changes expose project teams to unfamiliar legal and contractual hazards. This article surveys the most frequent delivery pitfalls and offers risk‑management tactics for architects, builders, and owners.
Code Fragmentation & Permitting Delays
The 2021 International Building Code (IBC) introduced three new tall‑wood construction types, IV‑A, IV‑B, and IV‑C, allowing buildings of 18, 12, and nine stories, respectively. In 2024, the IBC added a pivotal refinement by permitting 100% exposed timber ceilings in Type IV‑B occupancies, giving design teams greater freedom to celebrate wood finishes. Western jurisdictions have adopted the tall‑wood provisions on staggered timelines. Oregon fast‑tracked them statewide in 2018; California integrated them into the 2022 California Building Code; and Washington adopted them through its 2021 Washington State Building Code, which became enforceable on July 1, 2023. Because many cities layer additional amendments or demand peer review, two otherwise identical buildings can sail through plan review in Portland yet stall in Seattle.
Evaluation Reports Versus Local Amendments
Most cross‑laminated timber (CLT) and glulam products carry ICC‑ES or APA evaluation reports that certify compliance with prescriptive code paths. Some cities, however, impose stricter detailing such as additional char layers, concealed connectors, or lower percentages of exposed wood, which override those national approvals. Contract documents should therefore:
• State that listed products are acceptable to the extent permitted by the authority having jurisdiction.
• Include defined owner allowances for upgrades that local amendments may require.
• Confirm that fire‑test data cover any extended burn times or char‑rate factors mandated by local regulations.
Supply‑Chain Disruptions & Long‑Lead Claims
CLT panels, glulam columns, and metric screws follow international supply routes. Although pandemic‑era bottlenecks eased in 2024, lead times still fluctuate with mill capacity and wildfire shutdowns. An industry panel at the 2024 International Mass Timber Conference warned that shipment delays remain the primary schedule risk. Force‑majeure clauses should therefore name critical mass‑timber components expressly, and project schedules should include fabrication milestones that release payment only when production is independently verified.
Moisture & Fire‑Protection Quality Assurance
Factory‑built precision does not protect mass‑timber from moisture once it reaches site. Swelling, delamination, and fungal growth are the leading drivers of latent‑defect claims. Good practice includes roof‑first erection sequencing, daily moisture logs captured by embedded probes, and temporary membranes over every new floor plate. Requiring a water‑test mock‑up of facade and roof junctions before mass‑timber erection sets a quality benchmark and produces photographic evidence for future disputes.
Insurance Gaps & Higher Premiums
Developers consistently report that insurance, not code, is the largest hurdle for tall‑wood projects. Builder’s‑risk carriers unfamiliar with CLT often impose premium uplifts, sub‑limits for fire, or higher deductibles. WoodWorks’ 2025 Mass Timber Insurance Strategy Roadmap recommends workforce training, standardized QA checklists, and owner manuals as persuasive risk‑mitigation evidence. Practical contract measures include:
• Specifying builder’s‑risk terms in the request for proposals rather than at policy renewal.
• Sharing accredited fire‑resistance and seismic data with underwriters to narrow perceived risk.
• Securing endorsements that cover soft costs such as extended financing in the event of a covered delay.
Seismic Performance & Latent‑Defect Exposure
Along the Pacific Rim, building officials are entitled to require nonlinear dynamic analysis for tall‑wood lateral systems. Laboratory tests performed for the TallWood Project show that CLT shear walls with ductile steel connectors can exceed prescriptive drift limits, but the analytical model must match as‑built tolerances. Connection‑tolerance tables in shop drawings, a performance‑based‑design rider that caps the design professional’s post‑event liability at the fee earned and post‑occupancy sensor monitoring all reduce exposure.
Warranties, Maintenance, & Long-Term Liability
Mass‑timber ages differently from concrete or steel. Owners unfamiliar with moisture monitoring or pest management may neglect essential upkeep and later seek warranty relief. Delivering a maintenance manual that sets inspection intervals and moisture thresholds, limiting consequential‑damage liability for neglected maintenance, and reserving the right to inspect alleged defects before repairs proceed can prevent small issues from escalating into multi‑party litigation.
Conclusion
Tall‑wood construction delivers compelling environmental and aesthetic benefits, yet its novelty amplifies ordinary delivery risks. Mapping amendments early, aligning product approvals with local fire‑protection nuances, documenting moisture control, and addressing insurance hurdles at project inception allow Western project teams to embrace mass‑timber innovation without stumbling into avoidable legal pitfalls.