Thermory USA Names Cristian de Rosa CEO as North American Ambitions Accelerate

Thermory USA has appointed Cristian de Rosa as its new Chief Executive Officer, promoting a territory sales leader into the top job as the Estonian thermowood maker pushes to expand its North American footprint in both building products and sauna materials.

De Rosa joined Thermory in 2024 as Northeast and Great Lakes Building Products Territory Manager. In a press release, Thermory credited de Rosa’s “sound judgement, a strong work ethic and contagious energy” and said the board had been looking for ways to expand his role.

Challinor steps back, stays close

De Rosa succeeds Mark Challinor, the co-founder of Thermory USA who had been serving as interim CEO since 2025. Challinor now returns to his role as Chief Financial Officer while remaining on the board.

Challinor has been with Thermory USA since its founding. His public statements have consistently framed Thermory’s mission around displacing tropical hardwoods and chemically treated lumber with thermally modified alternatives.

Since he joined Thermory, Cristian has demonstrated sound judgement, a strong work ethic and contagious energy, and the Board of Directors has been looking for a way to increase his role at Thermory USA. Mark Challinor, co-founder and CFO, Thermory USA

Thermory’s sauna business

Most SaunaNews readers know Thermory, which describes itself as the world’s largest manufacturer of thermally modified wood and sauna materials, as a thermowood supplier for high-end sauna construction. Thermo-Aspen, Thermo-Magnolia, and Thermo-Alder bench boards and wall panels are common at sauna dealers across North America. The company also produces a line of barrel saunas, all now featuring upper bench configurations, an upgrade over the single low-bench designs common in the entry-level market. Thermory has also deepened its relationship with Homecraft, the Canadian heater maker, and has been courting the DIY sauna builder segment, which has emerged as one of the fastest-growing buyer categories in North America.

Sauna is only part of Thermory’s business. The company’s cladding, decking, and flooring divisions are the volume drivers, and those divisions are the ones where a territory-focused CEO could make the biggest difference. De Rosa’s background is in building products sales, not sauna specifically, which suggests where Thermory sees its biggest growth opportunity in the US market. More builders specifying thermowood for exteriors means more builders who know the material when they get asked about sauna projects. It is also the segment where Thermory now faces a newly localized challenger: Lunawood opened a thermowood production mill in Cleveland, Georgia in late 2025 and is pushing a North America Collection built around thermally modified Yellow Poplar and White Ash.

Recent US projects and products

In January 2026, the company announced that Thermory Thermo-Magnolia was selected for the Baltimore Ravens’ Under Armour Performance Center renovation, a 20,000-square-foot facility redesign by ZGF Architects that included custom sauna installations, hydrotherapy suites, and a design concept ZGF rooted in the structure of a raven’s nest. Custom bench boards were milled off-site for fast installation, helping the facility open ahead of the 2025 NFL season.

Then there is SaferWood with Thermex-FR, Thermory’s new ignition-resistant Class A benchmark pine that went to market in early 2026. The product is designed for California’s Very High Fire Hazard Severity Zones and wildland-urban interface areas, a segment short on real wood options that can pass fire code. Thermally modified wood was already partway toward fire resistance through the modification process itself.

Thermory also continues to exhibit at the International Builders’ Show, runs a growing DIY sauna builder program that puts its materials directly in the hands of owner-builders who want quality wood without a custom contractor markup, and runs the Thermory Design Awards for architectural projects.

How thermal modification works

Thermal modification subjects wood to temperatures between 350°F and 430°F in oxygen-free kilns using only heat and steam, with no chemicals, preservatives or pressure treatment. The process permanently alters the cellular structure of the wood, reducing moisture absorption, improving dimensional stability, and creating natural resistance to rot, decay, and insect damage.

The result is wood that performs like a tropical hardwood but comes from sustainable European forestry. Thermo-Aspen and Thermo-Magnolia are widely used for sauna benches and wall panels because they stay cool to the touch under heat, do not splinter, and will not warp in the 180°F-plus environment inside a properly built sauna. Thermo-Alder offers a richer color profile for builders who want warmth in the visual grain. None of these materials off-gas or leach chemicals when heated, unlike pressure-treated lumber, which has no place inside a sauna room.

Thermory has put more than 25 years and multiple generations of kiln technology into refining this process. When de Rosa talks about the “foundation” Challinor built, this is a large part of it: a supply chain that connects purpose-built European manufacturing capacity to an American dealer and builder network that is still learning the material.

A sales leader in the top job

Thermory is headquartered in Tallinn, Estonia, and the US is where it is pushing hardest.

Naming a field sales leader as CEO, rather than importing a finance executive or a European transplant, suggests that Thermory’s priorities in the US are about relationships, distribution, and market share. De Rosa knows the dealers, the territory managers and the builders who are specifying thermowood for the first time.

We are bringing in a new kind of energy and competitiveness, and we have the right people to do it. We have an outstanding team full of knowledge, ideas, and grit. Cristian de Rosa, CEO, Thermory USA