Decking is a widespread, popular feature of Australian custom homes. Since outdoor structures must be constructed from materials suitable for exposure to the elements, decking frames are most commonly made of H3 treated pine which is suitable for exterior above-ground use. For the in-ground parts, we have to use concrete, steel or durable timber species, such as cyprus, red gum, merbau or H4 treated pine. In high bushfire areas (BAL29 and above) we have to fully enclose the treated-pine frame (gaps up to 3mm are permitted) or use a bushfire resistant species of timber or steel.