The "H" rating for Treated Pine is an indication of the use to which the timber can be put and its resistance to rot and attack by termites or borers.

H1 products are for use indoors above gound. Typical use of H1 products include, framing, interior furniture and joinery. Resistant to insects other than termites.

H2 products are for use indoors above gound. Typical use of H1 products include, framing, interior furniture and joinery. Resistant to insects including termites.

H3 products are for above ground use outside exposed to the weather and dampness. Typical use of H3 products include, decking, fence pickets, fence rails, pergolas, exposed bearers and cladding. Resistant to rot and attack by termites or borers.

H4 products are for in-ground or ground contact use outdoors. Typical use of H4 products include, fence posts, sleepers, landscaping, garden edges and garden boxes. Resistant to rot and attack by termites or borers.

H5 products are for in-ground, in water contact and ground contact as structural support components. Typical use of H5 products include, retaining walls and building poles. Resistant to rot and attack by termites or borers.

H6 products are for prolonged contact with sea water. Typical use of H6 products include, piles, boat hulls, landings, jetty posts and cross bracing.

Where used appropriately and installed correctly treated pine products should last a lifetime or more. Most manufacturers of treated pine products offer guarantees against decay, termite and borer attack of 25 to 40 years.