High Pressure preservatives provide long term protection against wood destroying fungi and insects and are used in almost all end use situations (further information on Use Classes) The waterbased Osmose AC500 solution is applied to the timber in purpose designed industrial plants using vacuum and high pressure processes. This maximises the penetration of preservative into the timber and provides long lasting protection.

To select the correct specification please use the table below or download our Guide to High Pressure Treatment (PDF)

Treatment Code	Use Class	Typical Components
PT1	1 or 2	Internal building timbers, timber frame material, roofing timbers, TR26, tile battens.
PT2	3	Cladding, soffit, fascia and barge boards, Fence rails, decking, pergolas above ground contact. Farm buildings, stables, frames and sole plates above DPC.
PT3	1,2 or 3	Plywood and other suitable sheet materials
PT4	4	Ground contact timbers. Fence posts and gravel boards and any timbers in contact with the ground or below DPC level.
PT5	N/A	Australian Quarantine Standard (certificated)
PT6	Up to 4	Osmose Nature Wood treated timber with built in brown colour for fencing and landscaping timbers.
PT7	Up to 4	Retaining wall timbers

Desired Service Life for Osmose Nature Wood treated timber:
Components Used in Use Class 1 or 2 Up to 60 Years
Components Used in Use Class 3 15 - 30 Years
Components Used in Use Class 4 Up to 20 Years

Further information:
High Pressure Treatment Specification Guide(PDF)
High Pressure Treated Timber User Guide (PDF)