Hybrid mass timber is often the smarter structural choice. But it comes with a trade-off most teams just accept. The exposed steel beam. The run of ductwork overhead. A finished building that doesn't quite look like the one in the renderings. You wanted all wood. You got wood plus everything you had to leave showing.

Mike Lipke has spent over a decade making sure you don't have to accept that. He's the president and owner of TorZo Surfaces, the only U.S. manufacturer of Thin CLT panels. Thin sheets of cross laminated timber, available in almost any species, made from new material or remanufactured scrap. He's been making them since 2011, well before most people in the U.S. had heard of CLT.

In this piece Mike breaks down what Thin CLT actually is, the problems it solves on a jobsite, how it gets made from both new wood and salvaged material, and what the demand for it says about where mass timber is headed.

This article is just one part of the newsletter where we cover who and what’s shaping the mass timber industry.

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What Thin CLT Is and What It Solves

Thin CLT is a 4x8’ cross laminated timber panel ¾” thick (standard, they can make custom sizes too). It's designed that way to be familiar with crews used to working in standard plywood and OSB dimensions.

Most of the time, the job is cladding. In a mass timber building, that usually means covering up something that isn't wood. A steel beam. Concrete. Mechanical and HVAC ducting. You wrap it in a panel so it looks like mass timber. Most commonly, Mike sees it used as a beam wrap.

A lot of mass timber buildings put a steel beam in here and there, and the team wants it gone. Covered. Looking like the rest of the wood. Normally, that means using a different wood product (and mismatched look), or a full-sized mass timber piece that comes with a bigger price tag. But, with Thin CLT, you don't need the full-sized panel to maintain the consistent aesthetic.

On a big field nobody sees the edge of a panel in the middle of that wall, nor is it carrying any sizable load. There's no reason to pay for the structurally sized members there.

Instead, Mike laminates the exact same species, grade and finished material onto a cheaper backer, getting the exact same look, and saving the money. The whole wall looks like the same CLT construction as the main structure, even when most of it isn't.

How It's Made: New Wood and Salvaged Scrap

The new-wood process starts with standard dimension lumber. Two by fours, two by sixes, any species. Torzo re-saws it into thin layers, glues the strips into sheets, then laminates the sheets together in a normal 3-layer CLT pattern to make the panel.

You might be thinking, why not just use a single layer of the face material? In a perfect world, or with a perfect material, that would work. The problem is that wood isn’t perfect.

It moves. It drys. Bends. Warps. And twists. And then, no 2 pieces are alike. They do all that in different ways, times, and cycles. Using just the face material in a single layer would give you a very unstable material. Using multiple layers and putting the more “spirited” pieces in the middle stabilizes and distributes all that action across the panel and keeps it stable.

So when you want a “clear” panel look (no knots, checks, decolorization)  you can get a perfectly clear face while the knottier material goes inside (the middle) where nobody sees it. The face (and/or the back) match what the customer wants. And nothing gets wasted.

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Office buildings in major U.S. metros are sitting at roughly 20% vacancy. Data centers? Less than 1%. Right now, the U.S. is building data centers at a pace the construction industry has never seen, and no other commercial real estate category is close.

For the mass timber world, that's a real opportunity. The carbon math is there. Mass timber runs roughly 35 to 40% less embodied carbon than steel and up to 60 to 70% less than concrete. The buildings themselves run 500,000 to a million-plus square feet apiece. And the speed advantage of prefabricated mass timber lines up with one of the things data center owners need most: a lot of square footage built fast.

Erik Barth, AIA is one of the people figuring out what doing this well actually looks like. He's a Senior Associate at Gensler in Boston and leads the firm's Mass Timber Collaborative, a team that's been working on mass timber projects for roughly seven years. In this piece, Erik walks through where mass timber fits in the data center boom, why Type III construction has become the sweet spot, and how to design a building today that doesn't end up half-empty in 2040 for the same reasons a lot of office towers are now.

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Where Mass Timber Fits in the Data Center Boom

The demand picture for data centers is unlike anything else in commercial real estate. Computing power keeps growing, and that power needs a physical home. Storage and processing have to live somewhere, and they have to be close enough to power infrastructure and fiber to actually work.

That's why data center location is so constrained. Three factors have to overlap: serious power infrastructure, access to fiber cable, and affordable land. Where all three line up, you get a viable site. Most of the time that's outside major urban cores, which is why data center clusters form in specific regions rather than spreading evenly across the country.

Most of these buildings are one story, sometimes two.

Can the Structure Handle It?

One question that comes up with mass timber and data centers is whether the structure can handle the weight of high-density equipment. Erik's experience is that GPU and CPU loads are the defining structural driver, not the cooling system. His team solved for that with a five-ply CLT panel on a steel primary system, with a topping slab. That assembly handled the load comfortably for the projects they've worked on.

A single-story building is structurally simpler. You're basically putting a roof on a slab-on-grade. Two stories adds efficiency by stacking colos (colocations, the server rack groupings) but raises the structural complexity. Either configuration works for mass timber, depending on the site and the program.

The pitch for mass timber inside that program comes down to two things. First, the sustainability and biophilia story is real. Lower embodied carbon than steel or concrete, a positive economic impact for rural forestry communities, and a natural material that the operations staff inside the building actually get to be around. People don't always think about data center occupants because the buildings exist to house equipment. But these facilities need staff to monitor that equipment around the clock. You don't turn a data center off. The people working in them benefit from being around wood, especially over long shifts.

Second is speed. Mass timber gets prefabricated off-site and assembled on-site with smaller crews and shorter timelines than steel or concrete. For a building type that has to come online fast, that's a structural advantage in two senses of the word. The construction itself is also faster, lighter, and quieter, which makes mass timber a better neighbor in the communities where these buildings go up.

The case for mass timber in data centers is clear. The harder question is how to actually permit one.

The Code Path: Why Type III, Not Type IV

Code is where data centers get complicated. The scale alone is a challenge. You're talking about 500,000 to a million-plus square feet under one roof, with massive air handling, heavy equipment, and high power loads. Historically, data centers have been built as Type II construction.

When Erik's team started looking at mass timber for data centers, the obvious first instinct might have been the new Type IV subtypes that were written specifically for mass timber. In practice, Type IV created more problems than it solved.

The reason is air cooling. Most data centers running today use air-cooled systems, which require open plenum space for return air. Type IV doesn't allow a concealed plenum without fireproofing, which eliminates much of the efficiency that makes mass timber worth specifying in the first place. So Type IV and air-cooled data centers don't play well together.

Type III turned out to be the sweet spot. The primary structure doesn't need to be fire rated, which creates efficiency for connections, member sizing, and overall cost. The plenum space stays open. And the team was able to get the necessary square footage through a code variance.

Staying Ahead of a Moving Target

Data center technology is changing fast, and code is changing with it. Air cooling is the norm today, but liquid cooling is coming. Battery storage layouts are evolving, with some buildings centralizing battery rooms and others distributing them across the facility. Every one of those shifts has code implications for ratings, separations, and structural approach.

Erik's advice: stay involved in the discussions happening at the International Code Council (ICC). Don't get caught off-guard by updates. A static code strategy isn't going to hold up across a technology cycle this short.

The code path gets the building built. The next question is whether it still works ten years from now.

Designing for What Comes Next

There's a popular intuition that data centers are a temporary problem. The thinking goes: equipment keeps getting more efficient, so the buildings should eventually shrink or disappear. Moore's Law and all that.

Erik isn't seeing that on the ground. Yes, individual chips are getting more efficient per unit of volume. But the demand for both storage and processing keeps outrunning the efficiency gains, especially with AI. The support equipment around the racks isn't shrinking. So even as the technology itself gets better, the buildings aren't going away. They're just packing more capability into the same footprint.

That changes what future-proofing looks like. The primary job is designing the building to keep working as a data center as the equipment inside it evolves. Beyond that, there's a secondary benefit: a well-designed mass timber shell gives you optionality you don't get with other materials.

Mass timber helps with that in two ways. The first is end-of-life. Mass timber can be disassembled in ways that steel and concrete can't, which means materials can be reused if the building eventually does come down. The second is the building shell itself. A large structural grid and tall ceilings give you a clean, open shelf. Even within the strong design constraints of a data center program, that shell can support a wide range of future uses if the technology eventually shifts to something the building wasn't originally designed for.

Designing for the unknown takes discipline. The other half of getting this right is committing to mass timber from the start.

Commit Early or Don’t Commit

Erik's advice for owners and developers considering a mass timber data center comes back to one thing.

"It's important to commit to it up front. The sooner you can fully commit to a mass timber building and not look back, the more successful it's going to be and the more you'll be able to realize the efficiency that's inherent to the material."

Parallel costing and structural comparisons have their place. But the projects Erik has seen succeed have a team that picked the material, locked it in, and stopped re-evaluating it. The efficiency mass timber offers, in speed, in carbon, in build quality, only shows up when the team designs around the material from day one.

The early data center projects being built in mass timber today are proving the structural and operational case. The next phase is normalizing it. As more of these buildings come online, the precedent gets stronger, and the question shifts from “can mass timber work for a data center” to “why wouldn’t you build one this way.”

If you're exploring mass timber for your own projects, one of the first questions is often: who actually makes the materials?

To help with that, we created a Mass Timber Producer Map featuring 39 North American producers and fabricators. You can explore manufacturers near your project, see the products they produce, visit their websites, and connect directly with them.

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Most project teams don't know how to have the mass timber conversation with a skeptical fire department. And even when they do, it usually goes wrong, because by the time the meeting happens, it's too late to matter.

Erich Roden, retired Deputy Chief of the Milwaukee Fire Department and founder of Murphy Roden Group, took a meeting with the project team behind the Ascent (world’s tallest mass timber building) and has spent the years since walking other departments through that process.

Mason Brandt, P.E., President and Principal Engineer of WoodCore Engineering joins to bring the designers perspective to the table. He explains where, why and how to put mass timbers together to meet fire code AND give confidence to fire departments.

Between them, they cover where fire service skepticism comes from, what mass timber actually has to do at the connection and member level, what the Ascent project taught everyone involved, and what fire departments in unfamiliar markets need to see before they sign off.

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Where the Distrust Comes From

The fire service's caution around wood construction isn't abstract. It traces to specific fires, specific deaths, and specific lessons that got passed across generations of departments. On August 2, 1978, 6 firefighters died at the Waldbaum's Supermarket fire in Sheepshead Bay, Brooklyn, when a bowstring wood truss roof collapsed during a renovation fire. Twelve firefighters fell through the roof when the center section gave way; 6 made it out. A decade later, on July 1, 1988, 5 firefighters died at the Hackensack Ford fire in New Jersey when another bowstring truss roof collapsed. The adage that grew out of those fires, "don't trust the truss," is still being repeated in the fire service today.

That caution expanded as the residential industry shifted in the 1970s to light frame wood products. Departments started losing firefighters to floors that collapsed faster than expected. The wood industry, in the fire service's view, had a track record. Mass timber arrived carrying that legacy, even though the materials, the engineering, and the testing behind it look nothing like what came before.

Erich points to a parallel that gets missed. Type IV buildings, the post-industrial heavy timber type common in cities like Milwaukee, do not collapse in fires. The standard refrain from firefighters after a five-alarm fire in one of those buildings is some version of "I can't believe what a shellacking that building took, and it's still standing." The dimensional size of the lumber is doing the work. Those stories don't make the textbooks or the peer-reviewed journals, so the lesson never gets institutionalized inside the fire service.

Most firefighters working today inherited the distrust from older generations and are weighing mass timber against the lightweight construction era, not the heavy timber one.

Closing that gap means showing fire departments what mass timber actually does under fire conditions, starting with how the system holds itself together.

How Firefighters Look at Buildings

Mason brings up a common misconception. Concrete and steel don't burn, but that's not the same as "concrete and steel buildings don't fail in fires."

The three primary structural materials behave differently in a fire. Steel loses strength as it heats, elongating at high temperatures, which pushes outward on connections and walls and destabilizes the structure from the inside. Concrete spalls when superheated water inside the slab boils, exposing the rebar, which then heats and elongates the same way. Wood does neither. It loses section at a predictable rate (roughly 1 inch per hour), doesn't push walls outward, and starts extinguishing itself once the apartment contents are out.

What gives a fire department confidence to keep crews inside a mass timber structure comes down to a few things. Concrete stairwells give fire service teams confidence because it’s the beachhead they launch operations from. Sprinkler systems doing the lion's share of the work before crews even arrive. Connections without exposed steel, where openings and gaps in steel hardware are sealed up and protected from direct fire attack. And firefighting tactics that don't have to change.

When a fire department arrives at a fire, they don't think in material categories. They think in failure modes. What’s the building going to do as the fire burns? Where can my crew safely operate? What’s the sequence I'm watching for that tells me to pull out?

That’s the lens a fire department evaluates a structure through. It’s also the lens designers need to design through if they want a fire department's confidence.

For designers, the takeaway runs through every detail. Build for predictability. Detail connections that behave the way the rating says they will. Don't put exposed steel where it becomes the failure point. Provide cast-in-place stairwells where firefighters need them. The fire department's job is to understand the building as it burns. The design team's job is to make the building easy to read.

The performance is one thing. The Ascent project showed what it takes to get a fire department comfortable enough to approve it.

The Ascent Strategy

Erich calls it a Cinderella story. He was a battalion chief at the time. The fire chief's secretary asked him to come downtown. A local developer, New Land Enterprises, was proposing a 23-story wood building on one of Milwaukee's busiest avenues. The chief had questions and wanted Erich to handle them.

The first surprise came at the initial project meeting in the fall of 2018. The room had New Land, the architect (Jason Korb of Korb Architects), the structural engineering team (Thornton Tomasetti), and the rest of the design and approvals teams. The fire department had been pulled in, but not to sign off on a finished package. Partway through the meeting, Erich realized the building wasn't permitted yet. The team wasn't there to walk the fire department through a project that was already approved. They were there to hear the fire department's concerns before they got started.

That was the opposite of how those meetings normally go. The standard pattern is the fire department comes in at the end. New Land Enterprises flipped that. They wanted to know what the fire department was worried about, what they wanted to see during construction, and what they wanted in the final building. Erich raised the structure-during-construction concerns: sealing the building four floors below the active level, no debris, no smoking or grilling on site. New Land Enterprises agreed to all of it.

The second surprise was the testing. The developer needed variances to exceed the 2015 IBC, which Milwaukee was operating under at the time. The Ascent's design exceeded the code by a wide margin, so performance-based testing was the path. The Forest Products Lab in Madison ran the test. The team put one of the mass timber slated for the project into a furnace and ran it at 3,000°F for three hours. When they pulled it out and chipped away the char layer, the timber retained its structural integrity. Erich watched through the sight glass.

The trade New Land Enterprises offered to get the variance package signed was straightforward. Gypcrete in the public hallways, which firefighters use as a beachhead during operations. In return, two more stories. The building landed at 25.

The third surprise was construction. The Developer and the contractor (C.D. Smith) offered the fire department unlimited site visits. By the time the project finished, most of the firefighters in the city's 36 firehouses had been through it.

The result Erich points back to most often isn't the building itself. It's the conversion. The standard line from his crews after a tour was some version of "Hey chief, you know how much fire it would take to burn this amount of wood down?"

That sound bite, repeated across firehouses, did more for the fire service's view of mass timber in Milwaukee than any peer-reviewed paper could have.

What worked at Ascent is starting to translate to other markets, but the conversation looks different in cities that don't have a project like the Ascent yet.

Going East

Mason and his team are seeing roughly two to three times the project pipeline on the East Coast as on the West Coast. States with deep timber histories like Maine, New York, New Hampshire, Pennsylvania, and Virginia are showing serious project interest, along with Michigan, Wisconsin, and Minnesota in the Great Lakes region.

The fire service in those markets is moving too. Erich points to FDNY as the bellwether. A few years ago, when he gave a lecture with the head of buildings for New York City, the fire department's posture was a flat no. Not in my backyard. The concern wasn't ignorance about the material though. It was the institutional risk of being the official who signed off on a tall mass timber building in midtown Manhattan or downtown Brooklyn. The answer was no.

That’s changed. The most recent issue of WNYF, the FDNY's trade magazine, ran a mass timber piece that walks through what the buildings are, where the code is heading, and why the city is now involved in the research and code-writing for it. Erich's view is that as FDNY goes, the rest of the fire service follows. With the largest fire service in the country putting eyes on mass timber and engaging with the industry, the institutional posture downstream of that decision tends to follow.

For developers and design teams entering markets where the local fire department hasn't seen a mass timber project before, the strategy is pretty straightforward.

Bring the fire department in early, in the concept phase. Share the test data. Tell them which municipalities have approved similar buildings and offer to put them in touch. Walk through the firefighting operations and confirm that nothing about how their crews fight a fire in a tall mass timber high-rise is different from how they fight one in a Type IA building.  And invite the fire department onto the site during construction so their members get more comfortable with the system and products.

Mason adds the practical framing for why early engagement matters from a project standpoint. A developer who builds and flips moves on. The architect and engineer move on. The fire department is left with whatever has been built for the next 30 to 50 years. When fire departments get pulled in at the end, the relationship is adversarial by default. The dollars are committed and the design done. Bringing them in at concept gives them a chance to alleviate concerns before the project is shaped, which gets them to a productive role on the team rather than a defensive one.

The whole approach hinges on a single line Erich keeps coming back to.

What Fire Departments Need

The fire service's job isn't to stand in the way of economic development. It's to make sure the codes are enforced, the buildings are understood, and the firefighters who'll respond to the next call have what they need to do their work safely. Mass timber clears that bar. The buildings that have been built, the testing that's been run, and the projects like Ascent that pulled the fire department in early are the proof.

The instructions for any developer or design team stepping into a new market are short. Bring the fire department in early. Show them the data. Walk them through the building. Ask what they want to see. Let them ask their questions. The conversation goes faster than most people expect.

Erich's framing for the whole thing is one line.

"We're not gatekeepers. We can be convinced that these buildings are safe. Just show us and we'll understand."

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We have a housing problem. 

It's not because of zoning, not interest rates, not labor shortages — those are real, but they’re downstream. The upstream problem is that we still build buildings essentially the same way we did sixty years ago. Custom, on-site, one at a time. Every project is a snowflake.

If that’s the problem, then any real solution has to look fundamentally different from how the industry currently operates. It has to be industrialized. It has to be productized. And it has to scale across cities, not just succeed once.

Oliver David Krieg (OD) has been working on what that actually looks like for the better part of a decade. Now president of Intelligent City, he has a PhD in robotics in timber construction from Germany, and used to be the CTO at the company since 2018. Intelligent City is a Vancouver-based company that designs and manufactures flat-pack envelope and floor systems for multifamily buildings. Their project pipeline includes a 420-unit project in Ottawa and a 1,000-unit project in Barrie, Ontario — which, when it breaks ground, will be the largest prefabricated AND mass timber residential project in North America.

But here’s what’s interesting for us timber nerds.

Intelligent City didn’t pick mass timber because they love wood. They picked it because it was the right product decision for an industrialized building system. And that distinction matters more than it sounds.

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What “industrialized” actually means

The first thing to clear up is what we’re not talking about. Industrialization isn’t standardization. It doesn’t mean every building  needs to look the same.

“It just means the process that is underlying needs to be repeatable, not the result,” OD told me. 

The clothing industry is industrialized. So is the car industry. Both produce enormous variability for the customer while running highly repeatable manufacturing processes.

But multifamily construction has neither. It produces moderate variability (most apartment buildings look pretty similar) through a process that’s almost entirely custom every time. That’s the worst of both worlds.

Single-family housing is closer to being solved. Several European companies offer catalogs of 12 or so house designs with online configurators; you press a button and the building is engineered, cut and shipped. But single-family tends to sit on cookie-cutter lots with minimal constraints. 

Multifamily is harder because every building is a stack of unique combinations. Different sites, unit mixes, setbacks, parking requirements, etc. You can’t productize the whole building, or you’d lose all the design flexibility that makes each project work for its site.

What you CAN productize is components. Intelligent City’s bet is on the envelope panels and floor cassettes. Get those right, and you can erect and enclose a building dramatically faster than conventional methods, while preserving architectural flexibility on everything else.

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Why mass timber

This is where the material decision gets interesting.

Intelligent City didn’t start out to be a “mass timber company”. They were founded to solve a manufacturing and logistics problem. How do you build a flat-pack panelized system for mid and high-rise multifamily? That question dictated the material requirements.

The system needed something easily machinable, since no two projects require identical systems. It needed to be lightweight enough to flat-pack, ship cross-country, and install with reasonably-sized cranes. And it needed to be cost-efficient enough to move panels from a factory to a job site.

CLT was the only material that hit all three. Concrete was too heavy. Steel didn’t offer the same machinability for the panel format they needed. CLT was the consequence of the requirements, not the goal. The sustainability aspect of mass timber just happened to be the cherry on top of the product-fit sundae.

This reframes a conversation the industry has been having backwards. Most mass timber pitches lead with carbon, biophilia, or aesthetics. The arguments aimed at people who already want wood. But the stronger case for mass timber as a growth material might not be those values at all. Instead, it might be that it’s the right product decision for industrialized construction. If that’s true, the addressable market for CLT isn’t just clients who love timber or focused on carbon goals. 

It’s anyone trying to build housing at scale.

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Projects and Lessons

The proof point so far is 230 Royal York Rd in Toronto. Nine stories, 60 units, developed by Windmill Developments and Leader Lane under their Hauser brand. Manufactured by Intelligent City last year, now nearly complete.

It used 103 envelope panels in the building, and a floor goes up in a day. In theory, you could erect and enclose a 9–10 story building in about 30 days, cutting roughly three months off total construction time. That leads to real savings on general conditions, on financing, on time to lease-up.

That’s the theory. Royal York didn’t fully realize it. Not because of the system, but the scale of operations. 

Intelligent City’s Vancouver factory couldn’t feed the Toronto site fast enough. Shipping itself wasn’t the bottleneck — once panels were on a truck, two hours or forty hours didn’t really matter. The bottleneck was factory output. The demonstration plant they’d built to prove the system to developers was too small to deliver a building in Toronto at the speed the system was designed for.

That’s a setback worth being clear-eyed about. It’s also, OD argues, exactly the lesson he needed to learn before scaling.

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The next step

The demonstration plant in Vancouver is 15,000 square feet and produces 100–150 units a year. It was never intended to be the final version, only the start. It exists because no developer was going to sign with a prefab company that didn’t have a working factory, so they built the smallest one that could prove the system, and used Royal York to validate it.

The next factory — 100,000 square feet, targeting 1,000–1,200 units annually — is the commercial unit. Intelligent City’s goal is to greenlight the new factory this year and start deliveries in 2027.

That’s where the 420-unit Ottawa project and the 1,000-unit Barrie project sit in the timeline. They’re not built yet. They’re the projects the new factory is being built to deliver.

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What it would take

None of this is a silver bullet to housing… yet. This is one company doing amazing things. But the lessons here are something that can be applied industry-wide. 

The features that make Intelligent City credible as a model — productized components instead of fully productized buildings, in-house manufacturing, mass timber chosen on functional fit (not just feel-good points), and a demonstration plant before a full commercial factory are features any real solution to the housing problem will probably share.

OD’s long-term vision is a factory like the one he’s about to build in every major city in North America. A thousand homes a year is nothing against the total demand. The model has to be replicable, not a one-off.

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