To address the insufficient dimensional stability of thin solid wood flooring for ground heating system

including gaps

warping

cracking

and cupping caused by changes in ambient humidity. 12 mm thick

Pometia pinnata

wood was used as the material

pressure heat treatment was carried out at 230 °C

240 °C

and 250 °C for 7 min to modify the wood

which was then fabricated into thin solid wood flooring for ground heating system. The mass loss rate

chemical structure changes

surface wettability

dimensional stability

and mechanical properties of the wood

as well as the dimensional stability

thermal conductivity

and coating properties of the flooring

were evaluated. The results showed that pressure heat treatment had only a minimal effect on the mass loss rate of the wood

with the mass loss rate remaining be

low 2.47% even at 250 °C. Pressurized heat treatment significantly reduced the equilibrium moisture content

water absorption

and swelling rate of the wood (

P

<

0.05)

and these values decreased with increasing treatment temperature. This was attributed to the reduction in hydrophilic functional groups and moisture adsorption sites

as well as the increase in cellulose crystallinity induced by pressure heat treatment. In addition

pressure heat treatment at different temperatures caused varying degrees of microscopic damage to the cell walls

but had little effect on the mechanical properties of the wood. Compared with the control group

the test flooring exhibited significantly improved moisture-resistant and heat-resistant dimensional stability (

P

<

0.05)

meeting the requirements of the Chinese Standard GB/T 35913—2018 “

Technical requirements of solid wood flooring for ground with heating system

”. The thermal conductivity reached 11 °C·h

-1

satisfying the technical requirements of the Chinese Standard GB/T 41547—2022 “

Wood-based flooring for underfloor heating

”. The coating adhesion

hardness

and wear resistance showed no significant differences from those of the control group and met the premium-grade requirements specified in the Chinese Standard GB/T 15036—2018 “

Solid wood flooring-Part 1

:

Technical requirements

”.