OP-ED: What to Know About Oregon’s New CLT Construction Types
As the burgeoning market for cross-laminated timber (CLT) continues to build steam, Oregon has become the first state to provide an alternative pathway for constructing high-rise buildings from CLT and similar engineered timber products without obtaining special consideration.
More specifically, Statewide Alternate Method No. 18-01 (SAM 18-01), which was finalized in August, introduces three new construction types, all organized under the pre-existing “Type IV” code provisions for heavy timber structures. Prior to issuance of SAM 18-01, heavy timber structures were limited to a height of six stories. Under the new rules, Type IV ‘A’ buildings can be built as tall as 18 stories, Type IV ‘B’ buildings can be built as tall as 12 stories, and Type IV ‘C’ buildings can be built as tall as nine stories.
SAM 18-01 also adopts safeguards, manufacturing specifications, material conditions and design configuration prescriptions for the new building types. These include requirements for sprinklers and fire resistance, which vary depending on the height of the building. For example, Type IV ‘A’ buildings require three-hour, fire-resistance-rated primary structural frame elements and bearing walls, but Type IV ‘B’ and ‘C’ buildings require only a two-hour fire-resistance rating. Likewise, for Type IV ‘C’ buildings, exposed timber surfaces may remain entirely exposed, but for Type IV ‘A’ and ‘B’ buildings, these surfaces must be encapsulated in full or in part with fire resistant material. These are just a few samples of the myriad provisions applicable to the new hardwood structures permitted under SAM 18-01.
The new Type IV building types approved under SAM 18-01 significantly expand the number of projects for which CLT and other engineered hardwood products provide a viable alternative to structural steel, masonry and concrete. This is occurring while market demand for innovative materials is expanding at a rapid rate.
CLT and similar engineered timber products are made by layering dried timber, alternating the direction of grain between each, and bonding these layers into panels. Proponents of the materials laud their strength, dimensional stability, thermal and seismic performance, and low environmental impact. Another stated benefit of CLT is quicker installation, which may lead to lower production costs – a consideration that is especially important in an industry experiencing a shortage of skilled labor. As a result of these characteristics – and because they are resistant to compression – CLT panels are particularly well suited for multistory construction.
The hype surrounding engineered timber products appears to be catching on throughout Oregon, with several CLT projects – including the First Tech Credit Union building in Hillsboro and the District Office in the Central Eastside – currently under way in the Portland-metro area. Plus, other CLT buildings, including Carbon 12 and Albina Yard, have already been completed here.
Despite its popularity, CLT has suffered a few recent setbacks. Earlier this year, a large CLT panel that was to be used for subflooring in Oregon State University’s Peavy Hall failed during installation. The incident raised questions about the manufacturing processes and quality control standards for CLT. In addition, development of the 12-story Framework building planned for the Pearl District suddenly halted in July because of escalating construction costs and other market factors.
These hiccups notwithstanding, momentum seems to be in favor of continued growth in the market for use of CLT and similar engineered timber products in Oregon. And SAM 18-01 is another example of how Oregon has emerged as a leader in this particular industry niche. States without CLT-specific regulations and standards must rely on national building standards, which have yet to address CLT, effectively making the use of engineered wood products in those markets uncertain.
Earlier this year, the International Mass Timber Conference was held in Portland, bringing together key industry leaders to discuss these new innovations and their impact on the development and construction industries. The conference is being held in Portland again in 2019, and a review of the regulatory standards and potential solutions in light of the recent issues with CLT will undoubtedly be part of the ongoing discussion.
Further, the state of Oregon is quick to remind industry players that SAM 18-01 was created to help – not hinder – innovation. An August 2018 abstract provides that SAM 18-01 “intentionally reinforces the notion that the state building code is not a barrier to innovation or any method, technique or material of construction that is supported by scientific findings, while further preserving Oregon’s ability to serve as a single place to obtain statewide approval, providing a predictable regulatory system of business.”
Given the rise in popularity of CLT and engineered timber products, developers, contractors and manufacturers should pay close attention to SAM 18-01 and its new requirements. Due to the new provisions’ complexity, the best approach is to contact a construction attorney when attempting to interpret them or apply them to existing or prospective projects. Stakeholders don’t want to be caught flat-footed, especially given the current pace of construction.
Column first appeared in the Daily Journal of Commerce on September 25, 2018.
- Stephanie HolmbergIndustry Group Leader
- Jessie SchuhAssociate