How Engineered Wood is Replacing Steel and Concrete in the World's Newest Skyscrapers

The skyline of Milwaukee is changing, not with the familiar sparks of welding steel or the continuous pour of concrete, but with the quiet assembly of engineered wood. The Edison, a 31-story tower currently under construction, is set to become the tallest mass timber building in the world when it tops out in 2026.[1][2]

It represents a quiet revolution in architecture. For over a century, high-rise construction has relied almost exclusively on steel and concrete—materials that are incredibly strong but environmentally taxing. Now, a material known as cross-laminated timber (CLT) is challenging that dominance, offering a renewable alternative that could fundamentally alter how cities are built.[3][4]

What exactly is CLT? It is often described by architects as "super plywood." Manufacturers take layers of kiln-dried lumber and glue them together, with each layer oriented at a 90-degree angle to the one below it. This crosswise arrangement gives the panels exceptional strength, stiffness, and structural rigidity in both directions.[3][5]

These engineered panels can be massive—often manufactured up to 10 feet wide and 60 feet long—and are used to form the major structural elements of a building, including floors, walls, and roofs. When paired with glue-laminated timber (glulam) for columns and beams, the resulting "mass timber" system can support immense vertical loads and span significant distances without the need for traditional framing.[4][5]

The environmental stakes driving this shift are massive. The traditional materials of high-rise construction are produced by extractive industries that mine and heat raw materials, consuming vast amounts of energy in the process. Concrete production alone is responsible for an estimated 5% to 8% of all human-generated carbon dioxide emissions globally.[4]

Mass timber, by contrast, acts as an active carbon sink. Trees naturally sequester carbon dioxide from the atmosphere during photosynthesis. When those trees are harvested and engineered into CLT, that carbon remains locked inside the wood for the entire lifespan of the building—a phenomenon known as biogenic carbon sequestration.[6]

Studies indicate that substituting mass timber for concrete and steel can reduce a building's embodied carbon footprint by 35% to 50%. A single mass timber high-rise can sequester thousands of metric tons of carbon, an impact roughly equivalent to taking hundreds of gas-powered vehicles off the road for an entire year.[6]

But building skyscrapers out of wood inevitably raises a critical question: what about fire? The idea of a combustible high-rise instinctively alarms both the general public and regulators. However, mass timber behaves very differently in a fire than the light-frame wood used in traditional single-family homes.[4]

During a fire, the thick, solid panels of mass timber char on the outside. This charred layer acts as a natural insulator, protecting the structural integrity of the inner wood and drastically slowing the burn rate. Extensive performance-based testing has shown that CLT structures can withstand over 90 minutes of intense burning without collapsing, meeting or exceeding the safety standards required of concrete.[4]

This proven safety profile has prompted major regulatory shifts worldwide. In recent years, the International Building Code (IBC) was updated to officially approve mass timber for buildings up to 18 stories in the United States, ushering in a new era of architectural possibility and giving developers the green light to scale up.[4][5]

Beyond the environmental and safety metrics, urban developers are drawn to the sheer efficiency of the material. Because CLT panels are prefabricated in controlled factory settings using precise CNC machines, they arrive at the construction site ready to be slotted directly into place, much like a massive piece of furniture.[3][4]

This off-site manufacturing significantly reduces on-site build times. With the right logistical planning, construction crews can install over 1,000 square meters of CLT per day. The material is also up to five times lighter than concrete, which translates to smaller, less expensive foundations and reduced transportation costs.[3]

The aesthetic appeal is another major driver for the real estate market. Architects frequently choose to leave the structural timber exposed on the interior, creating warm, biophilic environments that connect occupants with nature. This visible wood has been shown to improve indoor air quality and tenant well-being, allowing developers to command premium rents.[3]

The Edison in Milwaukee, which will feature 350 residential units, is a prime example of this modern approach. It utilizes a hybrid structural system, combining a concrete core with CLT and glulam elements for the floors and framing, proving that mass timber can scale to unprecedented heights when engineered creatively.[1][2]

Yet, the mass timber movement is not without its long-term challenges. The true sustainability of the material depends entirely on responsible forestry practices. If the timber is sourced from clear-cut old-growth forests or monoculture tree farms, the ecological damage and loss of biodiversity can easily outweigh the carbon benefits.[6]

Forestry experts emphasize the critical need for a "circular economy" approach. By sourcing wood from sustainably managed forests—where harvest rates are carefully balanced by new growth—the industry can create economic incentives for private landowners to conserve working forests rather than selling them for commercial development.[3]

Additionally, the industry must grapple with the end-of-life treatment of these buildings. To maintain the carbon sequestration benefits indefinitely, the timber must be reused, recycled, or repurposed when a building is eventually decommissioned, rather than being sent to a landfill where it would decompose and release its stored carbon back into the atmosphere.[6]

As supply chains mature and manufacturing capacity expands across North America and Europe, the cost of mass timber is expected to reach full parity with traditional materials. For now, the rise of the "plyscraper" stands as one of the most promising developments in the fight to decarbonize the built environment, proving that the sustainable cities of the future might just be grown in the forest.[7]