Researchers at the Georgia Institute of Technology developed a method to use pressure treating lumber with metal oxide to make not only fungal-resistant, but also nearly impervious to water.

Pressure treating is a process to make timber resistant to fungi. Wood is placed in a pressurised watertight tank to force chemical into the material. This method has been used for over a century.

The new process borrows from a manufacturing technique of microelectronics for computers and cell phones, called atomic layer disposition. It involves applying a protective coating of metal oxide of only a few atoms thick throughout the entire cellular structure of the wood. Like pressure treatments, the process is performed in an airtight chamber, but uses less pressure to help gas molecules permeate the entire wood structure.

As the gas molecules travel down those pathways, they react with the pore’s surfaces to deposit a conformal, atomic-scale coating of metal oxide throughout the interior of the wood. The result is wood that sheds water off its surface and resists absorbing water even when submerged.

In addition to being hydrophobic, lumber treated with the new technique is also resistant to mould that eventually leads to rot. Additionally, the treated wood is less thermally conductive compared to untreated wood, and therefore a better thermal insulator.

Photos: Allison Carter / Georgia Tech