Thermawood-USA Solid waterproof wood

Thermawood-USA waterproof solid wood flooring is 100% real American hardwood, permanently changed using heat and steam. It isn’t vinyl. It isn’t engineered with a plastic core. It sands, stains, and installs like real wood — because it is real wood.

The difference is how it behaves.

Thermal modification changes the wood from the inside out, dramatically reducing how it absorbs moisture. That stability allows solid hardwood flooring to perform in places where traditional wood struggles when installed correctly, including bathrooms, basements, concrete slabs, radiant heat, and other high-moisture environments.

This isn’t a coating and it isn’t a surface treatment. It’s a permanent change to the wood itself.

WHAT “THERMALLY MODIFIED” MEANS

Thermal modification permanently changes how wood behaves, not by coating it, but by altering it from the inside out.

The wood is placed in a specialized kiln where oxygen is removed and heat is raised far beyond normal kiln-drying temperatures. Without oxygen, the wood can’t burn. Instead, the sugars and starches inside the wood are broken down.

Those sugars are what normally absorb moisture and feed decay. Once they’re removed, the wood takes on far less moisture and becomes dramatically more stable.

The result is solid hardwood flooring that doesn’t absorb water the way typical wood does. It won’t cup, warp, or twist, and it can be installed over concrete slabs, radiant heat, and in high-moisture environments.

Nothing is added to the wood.
No chemicals.
No plastics.
No surface treatments.

It’s still real hardwood flooring, just permanently improved with heat and steam.

WHERE THERMALLY MODIFIED FLOORING WORKS

Concrete slabs constantly release moisture, even when they appear dry. Thermally modified flooring resists that moisture uptake, helping prevent cupping, swelling, and distortion.

Radiant heat systems expose flooring to steady temperature changes that cause traditional hardwood to shrink or crack. Thermally modified flooring remains stable through those swings when installed correctly.

High-moisture environments are hard on conventional hardwood. Thermally modified flooring handles these conditions calmly, staying stable and predictable instead of swelling or warping.

That same stability is why thermally modified wood is used in spaces that transition from interior to exterior conditions, where moisture and temperature change throughout the day.

BATHROOMS, SHOWERS, AND WET AREAS

Bathrooms and wet areas are where traditional hardwood usually fails, not because of surface water, but because moisture gets trapped underneath and into the wood.

Thermally modified wood behaves differently, which is why it has been used successfully in bathrooms and shower-adjacent spaces when the system is built correctly.

Just like tile, stone, or concrete, the waterproofing system matters more than the surface material. When the substrate, membranes, drains, and transitions are properly waterproofed, thermally modified wood does not react to moisture the way standard hardwood does.

We’ve installed thermally modified wood in dozens of bathrooms, including shower-adjacent applications. When detailed correctly, the wood remains stable, holds its shape, and performs as intended.

This isn’t about hoping it survives.
It’s about building the system correctly, the same way you would for tile.

 

WHY REAL WOOD STILL MATTERS

Many flooring products labeled as “waterproof” today are plastic-based — vinyl, SPC, and composite materials designed to imitate wood. While they can resist surface water, they don’t behave like real hardwood. They look different, sound different underfoot, and age differently over time.

Thermally modified flooring takes a different approach. It keeps what people value about real wood — natural character, longevity, and the ability to be refinished — while solving the moisture-related problems that once limited where hardwood could be used.

After more than 40 years in the flooring business, we’ve said “no” to wood more times than we can count. Now, for the first time, we’re able to say “yes” and explain exactly where and why real wood can work.

Simply put, thermally modified wood is built to last the life of a home without contributing to the growing problem of plastic-based flooring and decking ending up in landfills.

Explore available species and applications:
White Oak, Antique Heart Pine, Cypress, Reclaimed White Oak, Red Oak, Shower Applications