Timber is an organic product and as such is subject to decay. In order to ensure its ongoing safe use in structural and external applications, various treatment processes have been developed. Depending on the nature of the exposure to insect and fungal decay different hazard classes have been identified.
According to the hazard class different amounts of preservative chemicals are used by the treatment plant.
- H2 - Interior above ground, eg. flooring, ceiling and mouldings
- H3 - Exterior above ground, eg. decking, fence slats and rails, exterior cladding
- H4 - Exterior ground contact, eg. poles and posts
Geelhoutvlei Timbers offers two options, one in house, and the other outsourced. Both are highly controlled pressure treatment processes controlled by the SABS and in accordance with SANS 1288 and SANS 753.
- TBTO clear solvent based preservative is used to treat ceiling and flooring to H2.
- CCA is a water borne inorganic formulation which is vacuum pressure impregnated into the wood offering long term protection across all hazard classes (H2 - H6) against wood borers, termites and wood decay. Geelhoutvlei Timbers uses the world famous TANALISED ® C brand.
In addition Geelhoutvlei Timbers uses the special additive TANALISED ® WEATHERWOOD ®. This water repellent additive provides greater moisture stability and reduces cracking in TANALISED ® timber.
Treatment on poles is guaranteed for 25 years. Treatment on sawnboard is guaranteed for 50 years. This guarantee operates either via the SABS or Koppers Arch, the makers of TANALISED ® C Brand
For more detail on the treatment process and the chemicals used please refer to Arch Wood Protection