Frequently Asked Questions — Decking
Merbau is a premium tropical hardwood prized for its rich reddish-brown colour, natural hardness (Janka ~8.5 kN), and built-in termite resistance — a classic choice for Melbourne outdoor decks. However, it requires annual oiling to prevent greying and surface cracking under Melbourne's intense UV and wet winters. Composite decking (WPC) is an engineered board made from wood fibre and recycled polymer. It is splinter-free, fade-resistant, and needs no staining or sealing — just an occasional wash. While Merbau delivers a warmer, authentic timber look, composite decking wins on long-term cost of ownership and is increasingly the preferred choice for Melbourne homeowners who want a premium outdoor space without the ongoing maintenance. BuildBarn stocks both — our team can help you choose based on your budget, lifestyle, and aesthetic goals.
Melbourne's climate — with scorching 40°C+ summers, high UV exposure, and wet winters — is particularly demanding on outdoor timber. Treated pine decking should be sanded and re-stained every 1–2 years to prevent splintering and moisture damage. Merbau hardwood requires oiling at least once a year to maintain its colour and prevent surface cracking. Composite (WPC) decking, by contrast, requires no staining, sealing, or sanding — a simple wash with mild soapy water once or twice a year is all that's needed. For Melbourne homeowners, composite decking offers the best long-term performance with minimal upkeep.
In Victoria, a building permit is generally required for any deck that is more than 800 mm above ground level, or exceeds 10 m² in area. For smaller, ground-level decks below these thresholds, a permit may not be required — but you should always confirm with your local council (e.g., City of Casey, Knox, or Greater Dandenong). BuildBarn can advise on appropriate structural timber sizes and grades that comply with the National Construction Code (NCC) and AS 1684. When in doubt, consulting a registered building surveyor is always the safest approach.
BuildBarn delivers to most Melbourne metropolitan suburbs within 24–48 hours. For outer Melbourne and regional Victoria, delivery typically takes 2–3 business days. We hold extensive stock of treated pine, Merbau, composite decking, and WPC cladding at our Hallam warehouse (3 Eastlink Drive), so same-day dispatch is available for in-stock items ordered before midday. Trade account holders receive priority scheduling and volume pricing — contact us to arrange a trade account today.
For standard residential decks with joist spacing at 450 mm centres, 90×19 mm decking boards are the most common and cost-effective choice. If your joists are spaced at 600 mm centres, upgrade to 140×19 mm boards for better rigidity and a premium aesthetic. For high-traffic decks, commercial applications, or longer spans, 25 mm-thick boards provide superior strength and reduced flex underfoot. Our team at BuildBarn's Hallam store can help you calculate the correct board size based on your frame design, load requirements, and budget.