Wood preservatives protect from biological attack, such as fungal and bacteriological damage.
The two main processes involved are:
- high-pressure vacuum treatment; and
- double-vacuum low-pressure treatment.
The preservative treatments used can be classified as:
- oiling; or
and these can be applied thus:
- brush and spray, as with painting, which requires repeating typically every four to five years; or by the use of preservative gels;
- deluge, dip, or steep for a short period of minutes, usually combined with organic solvent treatments;
- hot and cold open-tank method—used for fence posts, which are submerged in tanks, heated to 176–194ºF and simmered for two to three hours; the preservatives ...