H3

In Australia, H3 is a hazard level for treated lumber that indicates the level of protection against decay and insect attack. The H3 treatment is a medium-duty treatment and is suitable for use in above-ground, exterior applications where the timber is exposed to the weather but not in contact with the ground.

The H3 treatment process involves treating the lumber with a preservative that contains copper, azole fungicides, and a co-biocide. This treatment provides protection against decay fungi, borers, and termites.

H3 treated lumber is commonly used for a range of outdoor applications, including decking, fencing, and landscaping. However, it is important to note that H3 treated lumber is not suitable for use in applications where it will be in contact with the ground or exposed to marine borers. For those applications, a higher hazard level treatment, such as H4, H5, or H6, would be required.

H3 protects against termites and wood rot, and is for outside, above ground only.