Water damaged particleboard
By Discolapy, 02/01/2020
Direct contact with water is not needed for damage to occur: high humidity and water vapor, such as can come from a tea kettle or dishwasher, can also undermine particleboard.
The extent of damage depends on the composition of the board and the nature of the exposure to water.
Composition of the particleboard:
- Type binding material and wooden particles
- Structure (homogeneous vs. graded density), method of fabrication, age, and overall density of the particleboard
- Type of surface treatment (is the treatment water resistant?): no surface treatment, veneers , laminate, paint, paper
- Direct contact with water vs. exposure to humidity or steam
- Duration of water exposure
- Any additional stress on the particleboard (e.g. heavy object on a table made of particleboard). Wet/dry cycles?
- What happens after the exposure, for example did the particleboard dry under ambient conditions, was it heated or pressed?
Types of damage:
- Change of color
- Removal of surface layer (paint, veneer, etc.)
- Swelling 
Experiment: water exposure & drying
I dipped the particle board into a water bath (roughly 2 mm deep). A 3D printed support was employed to keep the board at desired position, see below:
The particle board was left 24 hours in the water bath. A camera was used to observe the swelling process. After 24 hours, water was removed from the bath and the particle board was left under ambient conditions (~21 °C) for another 14 days to dry.
I measured the thickness of the board both when it was partially-submerged, and also at 12-hour intervals when it was removed from the water and was drying. As a result, I have been able to plot the amount of swelling as shown by the increase in board thickness vs. time.
We can see that during the first hours of the “wet phase”, when the board was partially underwater, the thickness increased very rapidly. (Note that the initially measured thickness of “virgin” dry board was 16,3 mm and not exactly 16 mm as expected).
The first 3 hours of water exposure are very important. If the board is removed from the water within this interval, its thickness returns nearly to its initial state.
After about 6 hours, however, the damage is permanent. After about 24 hours the thickness of the particleboard had reached its maximum. Even if kept submerged longer, the thickness W will not increase (the swelling process has obviously its limitations). The maximum thickness was ~ 20.5 mm.
The first ~ 2 days of drying phase did not make a significant difference in particleboard thickness). The thickness slowly decreased as the water was removed from the particleboard material (mainly by diffusion). After about 14 days of drying there were no further changes to the boards thickness. Its new “dry” thickness is about 19 mm.
The particle board was now damaged permanently. The images below shows the board at 3 stages of the experiment:
- New particleboard – before exposure to water
- The board after 24 hours in the water bath. Note the color change near the border of the wet-dry margin
- The board after drying out for 14 days. Its thickness near the edge is 19 mm. Although the board is permanently damaged, it is still it is hard and remains reasonably functional from a mechanical point of view
- It is crucially important to remove water as soon as possible. After ~ 3 hours degradation is permanent. To that end it is very helpful to protect places through which water can penetrate the material with water resistant protection (paint). This slows down the process of sucking the water into the material.
- The process of drying is relatively long! In our case it took about two weeks until the thickness of the particle board reached its new “dry” thickness.
 A. Wagenfuehr, S. Tobisch, R. Emmler, B. Buchelt, T. Schulz; Vener in Interioe World; IFN; 2012
 B. Davis, R. E. Moon; Thickness Swell in Particle Board: A forensic Tool for the Duration of Loss; Forensic Engineering 2015
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