Both the bitumen lining and the lanolin oil treatments are non-toxic termite deterrents that don’t compromise organic certifications unlike CCA and other chemical treatments that leach into soils over time. The bitumen is a one-off internal treatment for the life of the bed that creates a water-resistant membrane to preserve the hardwood timber. The non-toxic lanolin oil is an exterior treatment to preserve (lock-in) the natural tannins in the timber. It can be applied once to prevent the natural tannins in the timber from leaching (washing) out if you prefer the timber to turn its silvery grey colour. Or, it can be applied once by us and reapplied annually by you once installed, if you want to preserve the original colours of the timber, and prevent greying.