Treated to H4 with Koppers Micro? Timber Treatment Technology, Lowdeck is protected from fungal decay, termites and insect attack. Suitable for in ground use and supported by a treatment warranty of 50 years. Engineered GL8 structural grade (roughly F7 equivalent) and double sealed with a high-quality oil-based primer to provide further protection. LOWDECK is an affordable, easy to work with alternative to steel or aluminium and is a smart upgrade from regular H3 Treated pine joists.