Why the Buzz about Mass Timber in MT?
Lessons from the Mass Timber Conference
by High Plains Architects
June 17, 2019
Welcome back to Billings, Ed! How was the Mass Timber Conference? Tell us all about it.
It was really good. I learned a lot.
Well…that was kind of terse. Can you tell us a little more? What was a major takeaway for you?
I was really struck by the magnitude of wood mass that grows every year in Montana compared to the amount that is harvested. If the forests are responsibly managed and harvested (and it’s important to include the qualifier “if”), we have the makings of a major, environmentally-sound industry that uses a widely abundant renewable resource in Montana.
Paul McKenzie, the Lands & Resource Manager at F.H. Stoltz Land & Lumber Co., detailed how the annual growth of wood mass in the national forests in Montana is 567 million cubic feet, the annual tree mortality is about 510 million cubic feet, and the annual amount harvested is 26 million cubic feet. So the growth is exceeding the removal at a 40:1 ratio. There is huge potential to displace a lot of fairly energy-intensive (and carbon-intensive) building products like concrete and steel with mass timber, and it can be good for our climate and other ecological services if we do it right.
So how do we do it right?
I am very committed to the various third party wood products certification programs, which ensure that forests are managed responsibly for habitat, watershed protection, and other ecological services as well as harvesting at a renewable rate. Stoltz Land & Lumber is certified by the American Tree Farm System program, which I’ve heard of but am not well-versed on yet. SFI, the Sustainable Forestry Initiative, is another certification program created by the forest products industry. Because much of the data it uses for certification is self-reported rather than third party, I’ve discounted the certification’s value in the past, although I suspect its best management practices have improved the industry.
But the gold standard for forest certification continues to be the Forest Stewardship Council (FSC) certification. Its principles and criteria cover not only habitat and watershed protection and sustainable yield but also indigenous people’s rights, community relations, and worker’s rights. And because of it third party verification as well as its standards, FSC had been the sole wood certification program that was recognized in the LEED® rating system. (That has changed with a pilot credit on legal wood in LEEDv4, so ATFS and SFI can now get credit in LEED.)
FSC certificated wood makes me happy to use wood without any reservation for almost any application, and so I would like to continue to educate clients on its value and use it whenever possible. Developing compliance plans, documenting compliance with the criteria, and paying for the third party verification adds some expense, of course. And so there are some smaller operators who may already follow most or all of the criteria who choose not to seek FSC certification due to cost. Unfortunately, however, there are currently no FSC certified forests in Montana, although there are an abundance in Idaho.
Who was at the conference?
I would estimate that there were somewhere between 50 and 75 people, but clearly I didn’t count. I met local economic development officials, the USDA Woodworks program regional director, structural engineers, general contractors, various manufacturers and fabricators that use wood, Montana Tech faculty doing materials research, and an importer of European wood products.
I also heard presentations from the Montana state forester and representatives from Senators Tester and Daines. One very noteworthy thing: everyone present seemed to be very enthusiastic about mass timber and its potential to provide an environmentally and economically sustainable industry for Montana.
What did you learn about the manufacture of cross laminated timber (CLT)?
One of the most valuable parts of the conference was the tour of SmartLam’s existing 40,000 SF CLT facility in Columbia Falls, MT. This SmartLam facility makes CLT panels in sizes of up to 10 ft. x 40 ft, and they can be customized for whatever notches or cutouts the design requires. I saw the 5 major stages of production of CLT in action:
Fingerjointing and Planing: The process starts with inspection of 2x6 and 2x8 lumber to delivered to the site for the grade (No. 2 or better), certification (SFI or FSC), and moisture content. Then, because the long boards need to be 40 feet long, the lumber goes through the fingerjointer. And then the nominal lumber is planed so that it has precise, square edges. Once it has been planed, the lumber needs to be laid up into a CLT panel within 12 hours for proper glue adhesion.
Composition and Pressing: In a device that resembles a 40 ft.-long waffle iron, four workers unload a forklift and organize a series of “longs” (the longitudinal boards). Then the glue trolley trundles along the length, depositing the correct amount of PureBond formaldehyde-free glue. And then a different forklift with “shorts” (the cross sectional boards) progressively advances as workers toss them onto the bed and order then side-by-side. And then the glue trolley trundles back. This process occurs until the 3-layer, 5-layer, or 7-layer sandwich is created. Finally, the panel gets pressed by the waffle iron at 30 psi for 45 minutes.
CNC Machining: After a panel has 12 hours to chillax and let the glue cure, it gets sent to the CNC (computer numerical control) machine, where it is tormented by a whole phalanx of saw blades and routers (4 heads, 5-axis). Each of the panels is precisely milled (3 mm tolerance) to the particular project design using the CAD shop drawing files that had previously been reviewed by the general contractor and design team.
Quality Assurance: Each of the outgoing panels is checked against the product specifications, and, as of this date, no improperly cut panels have been shipped to a jobsite. Speaking of shipping, the panels are then loaded on trucks in the reverse order that they will be needed on-site so that they arrive “just in time” at the site and can be lifted directly from the truck onto the building.
Quality Control: Most panels don’t actually go through this step, but there’s an on-site lab that tests panels periodically to make sure they comply with the specifications set out in the PRG-320 standard for CLT panels. This includes torturing panels with three different tests: 1) pulling finger-jointed boards apart to verify that they break at the wood fiber rather than at the glue joint, 2) a guillotine that tests block shear, and 3) cyclic delam test in which sections are weighed, super-saturated, baked in an oven, and then weighed again. The sections cannot delaminate and must be within 10% of their original weight.
And I got a special treat after the conference. Casey Malmquist, the president of SmartLam, gave interested attendees (which included me!) a tour of SmartLam’s new 140,000 SF facility that is partially outfitted. When it is fully operational in early 2019, it will be able to produce larger panels (10’x54’) at four times the current rate with the same amount of staff. I got to see the more fully-automated panel composition and pressing machinery, but I wasn’t allowed to take any pictures. (Shh--industrial secret!)
And did you learn more about using CLT in future High Plains Architecture projects?
Well, there are benefits to using CLT in addition to ones I mentioned in my last blog post, including:
Speed of erection: weeks can be shaved off of a construction schedule and often 25% faster to construct compared steel and concrete
Lighter weight: CLT is about 75% lighter than steel and concrete for a given application, meaning that foundations can be downsized considerably. This is especially helpful in places with soils with poor bearing capacity. It also means that erection equipment does not need to be as heavy-duty or expensive.
Structural efficiency: CT makes a very stout yet lightweight diaphragm without labor-intensive blocking. It also reduces the time and cost of inspecting structural systems.
I also confirmed that we can use CLT as a finish floor in multi-family residential project. We can even laminate a layer of wood species that is harder than pine onto the top. Sanding and finishing the floor on-site was highly recommended; even though SmartLam has the capability of applying a variety of coatings at the factory, a floor finish would get too beat up in the construction process.
Any other highlights of conference you want to mention?
Matt Miller, PE of Robert Peccia & Associates is the structural engineer we’re working on with our CLT projects, and he served on the Montana Professionals panel with me. He had a really good organizing device for his presentation: he walked through about 10 fairly recent projects he has worked on and talked about how CLT—had it been available—would have improved the projects in terms of construction schedule, quality of finish, and budget.
Concluding thoughts?
At High Plains Architects, we aim to design and complete buildings of significance. What are buildings of significance? They are:
durable
handsome
high performance
lovable
enhance walkability and community vitality
We do a lot of work with existing historic buildings that take care of some of those checklist items even before we get our hands on them. But there are lots of parking lots and other mixed-use infill opportunities, and I think CLT will be a key piece in delivering buildings of significance to Montana communities.