What is "Press Drying", and why did Junckers invent it?
What is Press Drying?
Press drying is a method that can be used for drying certain hardwoods. The process involves drying the wet staves under pressure in a large heated press for about two hours at 170°C.
Junckers solid Beech and European Maple floors are all press dried.
Origins
Early in Junckers’ history the Danish forestry industry tried to persuade wood product manufacturers to use wood that previously had gone to waste, namely smaller diameter logs and “thinnings” arising from forest management. This was “Environmentalism” long before the term had been invented. Beech, as a raw material was, and still is in plentiful supply.
The very first Beech floors that were manufactured by Flemming Juncker expanded and shrunk far more than those we manufacture today because Beech in its normal state is a “high movement” timber. Press drying solved this problem and has given us a much more useable material to work with. Enhanced stability along with our high levels of quality control are the reasons why our solid hardwood floors work so well with underfloor heating and may be laid in very large areas with guaranteed stability.
Why Is Press Drying Needed Today?
Press drying enhances a number of the wood’s qualities, making it especially useful for flooring.
- Reduces expansion and shrinkage by 60%
- Increases structural strength by 15%. Note that press dried beech is about 30% stronger than oak.
- Less waste- because the width of the staves does not shrink during the process- increases the amount of useable timber by 15% compared with conventional drying methods.
- Makes the colour of the wood warmer, more uniform and enhances the pattern of the grain.
- Provides a fast and very accurate way to dry the wood. The process takes about two hours, compared with 10 to 12 days for conventional drying.
Beech floors supplied by other manufacturers, be that solid or engineered, plank or parquet, will not be press dried. This means that they will have a high movement factor, and even when beech forms part of an engineered product tensions will arise within the board that may result in splitting and delamination.
Why Does Junckers Not Press Dry ALL Types of HardwoodThat They Use?
The overriding reason for using the process is to make our Beech floors more stable- and Press Drying does this perfectly. Other timbers such as Oak and Ash already have that stability so do not require it. Beech and Maple are very suitable for press drying because the cell structure allows moisture to leave the wood extremely quickly. Other woods such as Oak and Ash cannot be dried as fast and press drying can actually damage the staves.