Innovation Without Borders: WDE MASPELL and SII Dry Kilns Redefine Thermally Modified Wood

Imagine if common ash or oak could be transformed into a darker, more durable, and more dimensionally stable material using only heat and steam. This is the promise of thermally modified wood (TMW), a sustainable, chemical-free process that improves durability, stability, and appearance. Until recently, its potential was limited by technical challenges—particularly smoky odors and volatile organic compound (VOC) emissions—that kept TMW mostly for exterior use.

That’s where WDE MASPELL, an Italian manufacturer of thermal modification systems, and SII Dry Kilns, their U.S. partner, are making their mark. Speaking with Alessio Lucarelli, Commercial Director of WDE MASPELL, and Dan Mathews, Chairman of SII Dry Kilns, it’s clear that innovation and partnership are fueling a new chapter for the global hardwood industry.

Odorless, Health-Conscious Wood
“If you have no mass loss at the end of the process, you have no thermally modified wood,” Lucarelli explained. “But what sets our systems apart from competitors is that the VOC levels in the wood modified by our systems are almost the same as those in unmodified lumber. That means the wood from our kilns has virtually no smell.”

The implications are significant. Odor has long been a barrier to using TMW indoors, where flooring, paneling, and furniture need to perform well and be livable. With WDE MASPELL’s technology, thermally modified wood can now be used in interior settings without concerns about smell or the health risks from lingering gases.

A Design Advantage: Exotic Colors from Local Species
Thermal modification also alters wood’s color, deepening tones as the process nears 428°F—just below the self-ignition temperature. “This creates rich, exotic-like shades,” said Lucarelli. “Architects and project leaders often want the look of imported tropical species, but thermally modified wood allows them to achieve those aesthetics with local lumber.”

From oak and ash to southern yellow pine, nearly every species can be effectively modified—offering cost-effective options that strengthen local economies, reduce dependence on unsustainable imports, and broaden design possibilities for architects.

Proven Performance in the U.S.
The WDE MASPELL–SII Dry Kilns partnership has also been tested in the U.S. market. Mathews recalled a Pennsylvania customer who first invested in their technology for musical instruments, then scaled up for larger production. After briefly turning to a competitor, the customer returned in 2022. “They told us, ‘We made a big mistake. Whatever the cost, we need another of your systems,” Mathews recounted. “They had never seen such high-quality thermally modified wood as what came from our equipment.”

For buyers making significant capital investments, return on investment is paramount. Both Lucarelli and Mathews emphasized that their equipment consistently produces the highest quality TMW, ensuring customer confidence and long-term profitability.

Green by Process, Green by Product
Another advantage is sustainability, both in the product and the process. Thermal modification requires no chemical additives, meaning the resulting wood is eco-sustainable throughout its lifecycle. “Even after 25 years of use, it remains a green product,” Lucarelli said. WDE MASPELL’s process also eliminates gases and liquids, aligning with Europe’s stringent green transition policies and global sustainability goals.

Looking Ahead: U.S. Manufacturing
While demand in the U.S. was once limited, the last three years have seen significant growth. “The tide has come in,” Mathews noted. “Hardwood manufacturers are looking for new markets, and thermal modification is becoming an excellent path forward.”

WDE MASPELL has its sights set on U.S. manufacturing to meet that demand. “Our intention is to eventually produce equipment directly in the United States, with Italian technology, proudly manufactured in North Carolina alongside SII Dry Kilns,” Lucarelli shared. Though some time is still needed, the plan underscores how seriously both companies invest in North America.

A Partnership Built on Trust
Both leaders emphasized that the strength of their partnership has been central to success. “SII is not just an agent; they know kilns, they know the market, and they are reliable,” Lucarelli said. “When they speak, people listen.”
Mathews echoed the sentiment: “We’ve become good friends as well as business partners. That trust has allowed us to confidently introduce new technology, and it’s helping the industry grow.”

Conclusion
From odorless wood technology to exotic aesthetics and sustainable processes, WDE MASPELL and SII Dry Kilns prove that thermal modification has global potential beyond decking and siding. By expanding applications and raising quality standards, they are helping hardwood claim new ground in global markets and preparing the industry for the next wave of growth.

By BRENNAH HUTCHISON, Hardwood Industry Liaison & Content Director