Merbau Deck Construction in Hobart

The natural oils and tannins that make Merbau durable and termite-resistant need to leach out when the timber first gets wet. It’s like the timber’s settling into its environment. You’ll see brown water run-off for the first few months, maybe longer depending on how much rain we get. It stains pavers, render, whatever’s below. We can’t stop it completely – it’s part of the timber’s characteristics – but we pre-treat to reduce the intensity. Most of the bleeding’s done within 3-4 months, then it settles down. Some people hose their deck down regularly in the first few weeks to speed things up. The staining on surfaces below will fade over time with rain and weathering. If you’ve got light-coloured pavers or walls directly under where the deck will be, worth thinking about how you’ll manage that initial period.

Fresh Merbau’s got that gorgeous red-brown colour, but like all timbers exposed to UV and weather, it’ll start to grey if you don’t oil it. In Hobart’s climate, you’re looking at oiling once a year minimum, maybe twice if you want to keep the colour really vibrant. Use a good quality decking oil – not the cheap stuff from the hardware store, it won’t last. Clean the deck first, let it dry, then apply the oil following the manufacturer’s instructions. Takes a day usually, depending on your deck size. Some people love the maintenance ritual, others can’t be bothered – that’s fine too. If you let it silver naturally, it still looks good, just different. Silver-grey Merbau’s got its own character. You can always bring the colour back later with a sand and oil if you change your mind. The timber’s still durable underneath whether it’s oiled or not – the oiling’s just about appearance.

Yeah, Merbau performs really well in coastal areas around Hobart. The natural oils give it good resistance to salt air, and the density of the timber means it’s not as affected by moisture as softer species. We’ve built plenty of decks in Howrah, Bellerive, Lindisfarne – anywhere near the water – and they’re holding up well. You do need to use stainless steel fixings though, even more important in coastal locations. Regular steel will corrode fast with salt air, and you’ll get rust and staining. Also worth hosing the deck down occasionally to remove salt build-up, same as you would with any outdoor surface near the coast. The main thing with coastal properties is making sure water drains properly and you’ve got good ventilation under the deck – moisture management is everything in Tasmania. But the timber itself? Merbau’s a solid choice for coastal spots.

With proper installation and reasonable care, you’re looking at 25+ years, easily. We’ve got clients with Merbau decks that are 20 years old and still going strong. The Class 1 durability rating means the timber’s naturally resistant to rot and decay, which matters in Hobart’s wet climate. What’ll determine lifespan is mostly maintenance and installation quality. If you keep on top of oiling, make sure water drains properly, and the deck’s installed with proper gapping and ventilation, you’re setting it up for decades of life. Even if you let it grey out and don’t oil, the timber’s still durable – it’s more about appearance than structural integrity. The weak point’s usually the sub-structure, not the Merbau itself, which is why we use treated pine or hardwood for framing and make sure everything’s properly protected. Some of the oldest Merbau decks we’ve seen in Hobart are from the 90s and they’re still functional, just need cosmetic work. That’s the kind of longevity you’re investing in.

Individual boards can definitely be replaced if you get damage – split board, rot from poor drainage in one spot, whatever. That’s one of the good things about timber decking compared to composite. You can pull out damaged boards and slot in new ones. The tricky bit’s matching the colour – new Merbau’s obviously going to be redder than your weathered deck. Some people care about that, others don’t. If you’ve been oiling regularly, there’s less colour difference. If the deck’s gone silver, the new board will stick out for a while until it weathers. You can speed up the silvering process on new boards with some products, or just wait 6-12 months and it’ll blend in naturally. Structural repairs are straightforward too – if there’s issues with framing or posts, we can access and fix without tearing up the whole deck. The main thing’s catching problems early. If you see a board that’s looking wonky or you notice soft spots, get someone out to look at it before it becomes a bigger issue.