A new method of thickening wood and increasing its hardness has been developed at the Warsaw University of Life Sciences (SGGW). The solution will find application in the modification of materials used both in the construction industry and in elements of furniture, musical instruments and woodworking.

The new method is the original idea of Dr Marek Grześkiewicz from the Department of Technology and Entrepreneurship in the Wood Industry. It makes use of the effect of increased temperature on wood with a moisture content several per cent higher than in the final product. The heating leads to a softening of the lignin. The wood parts are then subjected to gradual, pulsed pressing, using high pressures, between the heated shelves of the press.

The entire process, depending on whether thin materials, such as veneers or facing boards, or parquet friezes and thick boards, are being pressed, lasts from several minutes to over an hour. Once modified, the wood is more resistant to fire and ignites later, but when it does ignite it gives off more heat.

The method can be applied to both natural wood and wood that has previously undergone various modifications, such as chemical or thermal modification. Interestingly, densified wood conducts heat better than natural wood. Therefore, modified wood flooring elements, parquet, solid floorboards can be used in rooms with underfloor heating, improving energy efficiency.

Compressed, compacted and hardened wood has significantly fewer pores in its volume, which means that far less finishing material is needed to protect its surface, for example by varnishing. And in the case of gluing components, less glue is sufficient. 

The developed method has been granted patent protection. The university is currently looking for partners – manufacturers of wood products, who would like to use the advantages of modified wood. 

Arkadiusz Słomczyński